 United States Court of Appeals
         FOR THE DISTRICT OF COLUMBIA CIRCUIT



Argued December 5, 2019            Decided December 27, 2019

                         No. 19-7110

                    SAMI ABOU-HAIDAR,
                         APPELLEE

                              v.

              MARIA EUGENIA SANIN VAZQUEZ,
                       APPELLANT


                 Consolidated with 19-7141


        Appeals from the United States District Court
                for the District of Columbia
                    (No. 1:19-cv-01687)


    Joseph J. DiPietro III argued the cause for appellant. With
him on the briefs was Sakeena Farhath.

     Stephen J. Cullen argued the cause for appellee. With him
on the brief were Kelly A. Powers and Leah M. Hauser.

    Sharon Swingle and Lewis S. Yelin, Attorneys, U.S.
Department of Justice, were on the brief for amicus curiae
United States of America.

    Before: MILLETT, PILLARD, and WILKINS, Circuit Judges.
                                 2

    Opinion for the Court filed by Circuit Judge PILLARD.

     PILLARD, Circuit Judge: The 1980 Hague Convention on
the Civil Aspects of International Child Abduction (Hague
Convention or Convention) seeks to “protect children
internationally from the harmful effects of their wrongful
removal or retention and to establish procedures to ensure their
prompt return to the State of their habitual residence.” Hague
Convention, T.I.A.S. No. 11670, S. Treaty Doc. No. 99-11,
preamble. The “problem with which the Convention deals . . .
derives all of its legal importance from the possibility of
individuals establishing legal and jurisdictional links which are
more or less artificial” in order to “change the applicable law
and obtain a judicial decision favourable to [them].” Elisa
Pérez-Vera, Explanatory Report ¶ 15 (Pérez-Vera Report). 1 To
combat this problem, the Convention seeks to achieve the
“restoration of the status quo” in international custody
disputes, id. ¶ 16, ensuring that courts of the child’s habitual
residence make the ultimate custody determination. A decision
pursuant to the Convention does not constitute a
“determination on the merits of any custody issue.” Hague
Convention, art. 19. Instead, the “central operating feature” of
the Convention is its petition remedy, through which a party
who claims a breach of custody rights may petition for the

1
  Elisa Pérez-Vera was the official Hague Conference reporter, and
the State Department has explained that her report “is recognized by
the Conference as the official history and commentary on the
Convention and is a source of background on the meaning of the
provisions of the Convention available to all States becoming parties
to it.” Dep’t of State, Hague International Child Abduction
Convention; Text and Legal Analysis, 51 Fed. Reg. 10494, 10503
(March 26, 1986). The Supreme Court has reserved the question of
what weight to accord the report, Abbott v. Abbott, 560 U.S. 1, 19
(2010), and we need not resolve that question here.
                               3
child’s return to the child’s country of habitual residence where
any custody adjudication appropriately would occur. Abbott v.
Abbott, 560 U.S. 1, 9 (2010).

     In this case, petitioner Sami Abou-Haidar claims that his
wife, María Eugenia Sanin Vazquez, wrongfully retained their
five-year-old daughter in the United States. The family moved
from France to the United States so that Sanin Vazquez could
fulfill an eighteen-month assignment as a consultant at the
Inter-American Development Bank in Washington, D.C. The
couple planned to live in the United States at least until Sanin
Vazquez’s contract with the Bank expired on December 31,
2019. Within six months of arriving in the United States,
however, the marriage began to deteriorate, prompting Sanin
Vazquez to take a series of actions—including unilaterally
filing for primary physical custody in D.C. Superior Court—
contrary to the couple’s previous, joint understanding of where
they would live together with their child. The district court
concluded that Sanin Vazquez’s actions constituted a retention,
and that the retention was wrongful because it breached Abou-
Haidar’s custody rights under the laws of the child’s habitual
residence, which the court held was France. Because Sanin
Vazquez has not identified any reversible error in the district
court’s factual findings or legal conclusions, we affirm the
district court’s judgment granting Abou-Haidar’s petition for
return.

                               I.

    In October 2013, Sami Abou-Haidar and María Eugenia
Sanin Vazquez married in Paris. Abou-Haidar, a citizen of
France, Italy, and Lebanon, is an emergency doctor who
provides house-call services. Sanin Vazquez, a citizen of Spain
and Uruguay, is a professor of Economics at the University of
Évry Val-d’Essonne, near Paris. The couple had a daughter in
                                4
Paris in early 2014. Before July 2018, the family lived
primarily in a rented apartment in Paris. The family also spent
several months at a time at a Barcelona apartment they owned,
but there is no serious dispute that France, not Spain, was the
family’s habitual residence before their move to the United
States.

     In January 2018, the Inter-American Development Bank
offered Sanin Vazquez a consultancy in Washington, D.C. The
initial contract offer was for an eighteen-month term,
renewable after a six-month period of separation. Because both
Sanin Vazquez and Abou-Haider thought Sanin Vazquez might
accept a renewal but only if it could be done continuously,
Sanin Vazquez renegotiated the Bank offer in early June 2018
to permit renewal, at the Bank’s discretion, for a second
eighteen-month term without a six-month period of separation.
With the renegotiated terms in hand, Sanin Vazquez agreed to
serve as a Bank consultant from July 1, 2018 through
December 31, 2019.

     The parties then took several steps to prepare for their
departure from France.          Sanin Vazquez requested a
détachement—a temporary assignment or secondment—from
her university for eighteen months, but maintained her
university affiliation, her doctoral students, and her French
pension. Abou-Haidar kept his Paris job but planned to work
for ten to twelve consecutive days each month in France and
spend the balance of the month in Washington. To reduce
costs, the couple rented out their Barcelona apartment for three
years and moved out of their rented Paris apartment, leaving
their furniture and large appliances in a storage unit in the same
building. For the days he would spend in Paris, Abou-Haidar
arranged to live in another, smaller Paris apartment that he
owned, which he otherwise continued to rent out during the
part of each month he spent in Washington.
                              5
     The couple took other steps in preparation for the move to
Washington. Sanin Vazquez obtained G-4 diplomatic visas for
the family valid for five years. As reflected in their text
messages and emails, the couple collaborated on finding a
residence to purchase in Washington, potentially with financial
assistance from Sanin Vazquez’s mother. After making an
unsuccessful bid on a house, they instead decided to rent an
apartment in the Woodley Park neighborhood. Abou-Haidar
took some initial steps toward obtaining a medical license in
Uruguay in anticipation of the family perhaps moving there
after Sanin Vazquez’s Washington consultancy, but he made
no effort to obtain an American medical license.

    The couple moved into their rented Washington apartment
on July 1, 2018 (shifting units within the building in March
2019). They enrolled their child in a nearby public Spanish-
English bilingual elementary school. The child is now nearly
six years old, has friends at her school, and participates in
soccer and other extracurricular activities.

     By December 2018, however, the couple began to
experience marital discord. As the marriage deteriorated,
Sanin Vazquez unilaterally took action to establish her primary
physical custody over the child. On May 2, 2019, Sanin
Vazquez filed a Complaint for Custody in D.C. Superior Court,
seeking “primary physical custody” and “joint legal custody”
of the child. J.A. 915. Sanin Vazquez did not tell Abou-Haidar
about the filing until five days later when, on May 7, she
notified him of the complaint and of her desire for a marital
separation. Immediately thereafter, Abou-Haidar received
service of the Superior Court complaint. On May 10, Sanin
Vazquez told Abou-Haidar that she planned to stay in
Washington, D.C. with their daughter after December 31
instead of returning to France. Finally, on May 31, Sanin
Vazquez’s family law attorney wrote to Abou-Haidar that their
                               6
Washington apartment had “never been the marital residence”
and that Sanin Vazquez had “changed the locks on her
apartment.” J.A. 1296.

     Abou-Haidar responded to these developments with
several actions of his own. First, on May 23, 2019, Abou-
Haidar filed an answer and counterclaim in D.C. Superior
Court, seeking “joint physical and legal custody” of their
daughter. J.A. 81-85. Then, changing course on June 6, Abou-
Haidar withdrew his Superior Court answer and counterclaim
and instead sought assistance from the French Central
Authority, the entity designated by France under the Hague
Convention to collaborate across international borders to
process applications arising under the Convention. See Hague
Convention, arts. 6-8. On June 10, before hearing back from
the French Central Authority, Abou-Haidar also filed a Hague
Convention petition in the U.S. District Court in Washington
for return of their daughter to France. As urged by the
Convention, the district court scheduled the case for prompt
disposition. See Hague Convention, art. 11 (encouraging
courts to rule on petitions within six weeks). Following that
filing, the D.C. Superior Court stayed any determination of the
custody aspects of Sanin Vazquez’s complaint pending
resolution of this case. About two weeks later, the French
Central Authority dismissed Abou-Haidar’s application in a
one-page letter, stating that the “presence of your daughter in
the United States is not unlawful since it was decided by the
parental couple which holds the parental authority.” J.A. 1015.

     The district court held an evidentiary hearing on August 1-
2, 2019. In a brief August 21 order, which the court specified
would be followed by a more detailed opinion, the court
concluded that Abou-Haidar had “proven by a preponderance
of the evidence that the mother, Respondent María Eugenia
Sanin Vazquez, has wrongfully retained [the child] within the
                                7
meaning of the Convention.” J.A. 150. Specifically, the court
held that Sanin Vazquez had retained the child on May 7, 2019
when she served Abou-Haidar with her Superior Court
complaint, or at the latest on May 23, 2019, when Abou-Haidar
filed his Superior Court answer and counterclaim seeking to
maintain joint custody. J.A. 152 & n.1. The court further held
that the child’s habitual residence was France because, “based
on the full record,” the “parties did not leave France in a
manner that would suggest a shared intent to relocate
indefinitely to the United States,” and evidence of the child’s
acclimatization to the United States did not supplant that intent.
J.A. 153-54. Finally, the court held that the retention was
wrongful because Sanin Vazquez did not dispute that the
retention violated the French custodial rights that Abou-Haidar
was exercising at the time of the retention. J.A. 154.

     The district court ordered the parties to confer and agree
on a date for the child’s return to France. On October 9, 2019,
the district court issued its Findings of Fact and Conclusions of
Law. J.A. 161-82. Because the parties had not settled on a
return date, the district court at that time also ordered the
child’s return to France by December 31, 2019. J.A. 183.

     Sanin Vazquez timely appealed both the district court’s
August 21 and October 9 orders, and the appeals were
consolidated. She also sought and received expedited
consideration from this court so that the district court’s
decision could be reviewed prior to the expiration of her first
Bank contract on December 31. On December 4, we invited
the United States to offer its views on the legal questions in this
case. 2 We heard argument on December 5 and now affirm the
district court’s judgment.


2
 We thank the government for promptly submitting an invited
amicus brief on short notice.
                                   8
                                  II.

                                  A.

     The Hague Convention, adopted in 1980, seeks to “secure
the prompt return of children wrongfully removed to or
retained in any Contracting State” and to “ensure that rights of
custody and of access under the law of one Contracting State
are effectively respected in the other Contracting States.”
Hague Convention, art. 1. The Convention is “especially
aimed at the unilateral removal or retention of children by those
close to them, such as parents, guardians, or family members.”
Gitter v. Gitter, 396 F.3d 124, 129 (2d Cir. 2005) (citing Paul
R. Beaumont & Peter E. McEleavy, The Hague Convention on
International Child Abduction 1-3 (1999)). Decisions under
the Convention do not resolve the underlying custody
disagreement. See Hague Convention, art. 19. Rather, the
courts of the Contracting States apply the Convention to
determine the lawful forum to decide international custody
disputes. The Convention directs that they do so by reference
to the status quo preceding the unilateral actions that gave rise
to the dispute. Id., art. 3.

    More specifically, the Convention creates two routes by
which a parent may act to ensure that the courts of the state that
was the child’s habitual residence make the ultimate custody
determination. 3     First, the Convention requires each
Contracting State to set up a “Central Authority.” Id., art. 6.
Those entities are required to “co-operate with each other and

3
  We use “parent” as a shorthand here and throughout because
parents are the typical parties on both sides. But our shorthand
should not obscure that the Convention covers all situations where
anyone wrongfully removes or retains a child in “breach of rights of
custody attributed to a person, an institution or any other body, either
jointly or alone.” Hague Convention, art. 3(a).
                                9
promote co-operation amongst the competent authorities in
their respective States to secure the prompt return of children.”
Id., art 7. A person seeking relief under the Convention may
file an application with a Central Authority, which may, among
other functions, help to “discover the whereabouts of a child,”
“bring about an amicable resolution of the issues,” and arrange
for the child’s “safe return.” Id. Applications may be refused
“[w]hen it is manifest that the requirements of this Convention
are not fulfilled or that the application is otherwise not well
founded.” Id., art. 27.

     Second, and relevant here, the Convention also authorizes
individuals to petition the judicial or administrative authorities
where the child currently is located for return of the child to her
place of habitual residence. Id., art. 12. An order requiring
return is appropriate only where the petitioning parent can
demonstrate that the child has been “wrongfully” removed or
retained. Despite its charged valence, “wrongful” removal or
retention is a term of art defined in the Convention that need
not involve what is usually thought of as “abduction.” The
“retention of a child is to be considered wrongful” where, as
applicable here, “it is in breach of rights of custody attributed
to a person . . . under the law of the State in which the child
was habitually resident immediately before” the retention. Id.,
art. 3. The Convention further defines “rights of custody” to
encompass “rights relating to the care of the person of the child
and, in particular, the right to determine the child’s place of
residence.” Id., art. 5(a). Finally, Article 12 of the Convention
provides the return remedy to address situations of wrongful
removal or retention, stating that where “a child has been
wrongfully removed or retained in terms of Article 3” and a
petition has been filed within a year of the removal or retention,
the “authority concerned shall order the return of the child
forthwith.” Id., art. 12; see generally Chafin v. Chafin, 568
U.S. 165, 168-69 (2013).
                               10
     Later sections of the Convention provide for exceptions to
this remedy of return “forthwith.” Hague Convention, art. 12.
As the Supreme Court has summarized, “Return is not required
if the parent seeking it was not exercising custody rights at the
time of removal or had consented to removal, if there is a ‘grave
risk’ that return will result in harm, if the child is mature and
objects to return, or if return would conflict with fundamental
principles of freedom and human rights in the state from which
return is requested.” Chafin, 568 U.S. at 169 (citing Hague
Convention, arts. 13, 20); see also Lozano v. Montoya Alvarez,
572 U.S. 1, 5 (2014). None of those exceptions is raised in this
case.

     Both the United States and France are Contracting States
to the Hague Convention. Each has set up a Central Authority,
as required, to receive Hague Convention applications. After
ratifying the Convention in 1988, the United States
implemented its provisions through the International Child
Abduction Remedies Act (ICARA), 102 Stat. 437, 22 U.S.C.
§ 9001 et seq. Consistent with the Convention, Congress
declared in ICARA that the “Convention and this chapter
empower courts in the United States to determine only rights
under the Convention and not the merits of any underlying
child custody claims,” id. § 9001(b)(4), and insisted that
“[p]ersons should not be permitted to obtain custody of
children by virtue of their wrongful removal or retention,” id.
§ 9001(a)(2). In addition, Congress specified how Hague
petitions may be filed in the United States, giving state and
federal courts concurrent jurisdiction to hear such claims, id.
§ 9003(a), and requiring that courts “decide the case in
accordance with the Convention,” id. § 9003(d). Congress also
specified that the burden is on the petitioner to “establish by a
preponderance of the evidence” that the child “has been
wrongfully removed or retained within the meaning of the
Convention.” Id. § 9003(e)(1)(A). Finally, Congress provided
                              11
that, where that burden is met, the child is to be “promptly
returned unless one of the narrow exceptions set forth in the
Convention applies.” 22 U.S.C. § 9001(a)(4).

                              B.

     This is the first case arising under the Hague Convention
that has reached our court. In interpreting the Convention’s
and ICARA’s various requirements, other circuits often distill
analysis of whether a petition for return should be granted into
a four-part inquiry, which the parties from the outset have
expressly embraced and continue on appeal to agree is
applicable:

    (1) When did the removal or retention at issue take
    place?

    (2) Immediately prior to the removal or retention, in
    which state was the child habitually resident?

    (3) Did the removal or retention breach the rights of
    custody attributed to the petitioner under the law of
    the habitual residence?

    (4) Was the petitioner exercising those rights at the
    time of the removal or retention?

Mozes v. Mozes, 239 F.3d 1067, 1070 (9th Cir. 2001); see also,
e.g., Monzon v. De La Roca, 910 F.3d 92, 100 (3d Cir. 2018);
Redmond v. Redmond, 724 F.3d 729, 737-38 (7th Cir. 2013);
Barzilay v. Barzilay, 600 F.3d 912, 917 (8th Cir. 2010); see
also U.S. Amicus Br. 25.

     The district court in this case granted Abou-Haidar’s
petition for return. The court concluded that Sanin Vazquez
retained the child when she informed her husband of her
                              12
Superior Court complaint on May 7, 2019, or at the latest when
Abou-Haidar filed his answer and counterclaim in D.C.
Superior Court on May 23, 2019. J.A. 172. The court also
found that the child’s habitual residence was France. J.A. 179.
On appeal, Sanin Vazquez challenges the district court’s
findings only with respect to the first two questions. Regarding
the first question, Sanin Vazquez takes issue with the district
court’s retention-date determination. Regarding the second
question, Sanin Vazquez and Abou-Haidar agree on the legal
standard that should apply—despite some international and
circuit-court conflict on the matter. Sanin Vazquez argues only
that the parties intended to abandon France when they moved
to Washington, D.C.

     As for the third question, Sanin Vazquez belatedly
attempts to argue that she does “not agree that [Abou-Haidar’s]
custodial rights under French law were or would be violated by
any of her actions or statements.” Reply Br. 9-10. But she
forfeited that argument by not disputing in the district court
“whether, if [the child was] wrongfully retained, Petitioner’s
custody rights under French law would be violated,” J.A. 171.
Indeed, Sanin Vazquez’s counsel affirmed to the district court
that Abou-Haidar had custody rights and that Sanin Vazquez
was raising arguments only under the first two questions, J.A.
650-51. In any case, the unrefuted Affidavit of French Law
Abou-Haidar submitted to the district court independently
supports the conclusion that an order granting Sanin Vazquez’s
Superior Court complaint unilaterally seeking “primary
physical custody” would diminish Abou-Haidar’s custodial
rights under French law. That Affidavit explains that, “[u]nder
French law, both parents have joint rights of custody,” and that
the “breakdown of a marriage or a relationship has no impact
over the rules governing the exercise of parental authority.”
J.A. 89-92; see also J.A. 102 (reproducing relevant sections of
the French Civil Code); Hague Convention, art. 5(a) (defining
                               13
“rights of custody” broadly to “include rights relating to the
care of the person of the child and, in particular, the right to
determine the child’s place of residence”). And, with respect
to the fourth question, the district court found that the parties
do not contest whether the “Petitioner was exercising his
custody rights at the time of wrongful retention.” J.A. 171.
Our analysis therefore addresses only the first two questions,
concluding that the district court did not err in finding that
Sanin Vazquez retained the child in May 2019 and that the
child’s habitual residence was France.

                               III.

     Sanin Vazquez’s primary contention is that the petition
must be dismissed because the district court’s retention date of
May 7, 2019, precedes December 31, 2019, the date through
which the parties agreed the child would remain in the United
States. Sanin Vazquez views this concern as jurisdictional,
arguing that the dispute “is not ripe until January 1, 2020
passes.” Sanin Vazquez Br. 34. In her view, recognizing a
retention date prior to December 31, 2019, would constitute an
“anticipatory retention”—a type of claim that, she asserts,
American courts have never previously recognized. Id. at 26-
27.

     We do not embrace Sanin Vazquez’s effort to label her
argument in jurisdictional terms; at bottom, her argument is
simply about whether a retention occurred, and thus goes to the
merits of Abou-Haidar’s Hague Convention petition. In any
event, we do not believe that the district court reached out to
decide an unripe issue when it identified a retention of the child
as of May 7, 2019—or, at the latest, May 23, 2019—because
this case involves an actual, rather than anticipatory, retention.
See U.S. Amicus Br. 25-29 (agreeing that this case involves an
actual retention). No court has held that either of these
                               14
retention dates would be premature. The circuits identify the
date of retention as “the date consent was revoked” or when the
“petitioning parent learned the true nature of the situation.”
Palencia v. Perez, 921 F.3d 1333, 1342 (11th Cir. 2019). For
example, the Second Circuit has held that the date of retention
is the date when the retaining parent advised the other that “she
would not be returning with the [c]hildren” as originally
planned. Marks ex rel. S.M. v. Hochhauser, 876 F.3d 416, 422
(2d Cir. 2017). Similarly, the Third Circuit identifies the
retention date as the “date beyond which the noncustodial
parent no longer consents to the child’s continued habitation
with the custodial parent and instead seeks to reassert custody
rights, as clearly and unequivocally communicated through
words, actions, or some combination thereof.” Blackledge v.
Blackledge, 866 F.3d 169, 179 (3d Cir. 2017). These cases also
find support in the official commentary of the Convention. See
Pérez-Vera Report ¶ 108 (stating that the date of retention is
when a “holder of the right of custody refused to agree to an
extension of the child’s stay in a place other than that of its
habitual residence”).

     The circuits also agree that the parental actions that serve
to identify such date need not be particularly formal. The
withdrawal of consent to existing custody arrangements may
be communicated through an in-person conversation, Darin v.
Olivero-Huffman, 746 F.3d 1, 10 (1st Cir. 2014), or an email,
Marks, 876 F.3d at 417-18, or a phone call, Palencia, 921 F.3d
at 1337. More formal actions would also certainly qualify,
including unilaterally filing for custody, Mozes, 239 F.3d at
1070, or filing a petition under the Hague Convention for the
child’s return, Blackledge, 866 F.3d at 179.

     Guided by these analyses, the district court correctly found
that Sanin Vazquez retained the child at the earliest on May 7,
2019, when she informed Abou-Haidar of her Superior Court
                               15
filing seeking “primary physical custody,” J.A. 915, or at the
latest by May 23, 2019, when Abou-Haidar filed his answer
and counterclaim making clear that he opposed the proposed
change to his custody rights, J.A. 152 n.1, 172-73. If there were
any doubt as to the precise date, other events further support
the district court’s conclusion that, by the end of May 2019,
both parents understood they disputed the exercise of custody
over the child: Sanin Vazquez informed Abou-Haidar on May
10 that she did not intend to return the child to France at the
end of the year, J.A. 170; Sanin Vazquez’s counsel wrote a
letter to Abou-Haidar on May 31 reiterating that Abou-Haidar
was not welcome in the Washington apartment where the child
was living with her mother, J.A. 1296; and, on June 10, Abou-
Haidar filed his petition for the child’s return to France, J.A.
10-32. Given the temporal concentration of these events and
the lack of any material effect on the analysis of choosing one
date over another, we need not isolate one definitive act of
retention. Under any circuit’s existing law on the point, one or
more of these actions suffices to identify a retention. See
generally Redmond, 724 F.3d at 739 n.5 (noting that an
‘“abduction’ might have occurred on one of several dates; the
question is always whether there was any date on which a
wrongful removal or retention occurred”).

     These facts also distinguish the case before us from the
case on which Sanin Vazquez principally relies, Toren v.
Toren, 191 F.3d 23 (1st Cir. 1999). The terms of the Toren
parents’ divorce called for the children to live with their mother
in the United States for a few years, with visitation by the
father, and provided that, by July 21, 2000, the children would
return to Israel where their father lived and attend school there.
See id. at 25. The mother filed a family-court action in
Massachusetts in 1997 to alter the terms of the father’s
visitation, and the father responded by filing a Hague petition
asserting wrongful retention. See id. at 27. The court held that
                                16
the petitioner had “failed to allege facts sufficient to set forth a
claim that the Toren children have been removed or retained
within the meaning of the Hague Convention” because the
mother had nowhere suggested that she would not return the
children to Israel in 2000 as agreed. Id. at 27-29. The father
pointed only to vague future “intention[s]” on the part of the
mother to retain the children. Id. at 27. Here, in contrast, a
series of decisions and corresponding actions already taken by
both parties clearly conveys a ripe disagreement about where
the child’s custody will lie. As Abou-Haidar observes, the First
Circuit’s dismissal in Toren is therefore consistent with the
basic principle that, in order to be ripe, a challenge to an
“anticipatory retention requires a clear communication that the
retaining parent is not returning the child home.” Abou-Haidar
Br. 32.

     The thrust of Sanin Vazquez’s argument is not that the
district court misapplied these tests in identifying the date of
retention, but that no retention is possible before the date
through which the parties initially agreed that the child would
reside in the United States. There is some intuitive logic to the
notion that, when the parents agreed that the child would
remain in a certain place until a specified date, no retention
occurs before that date as long as the child remains there. The
fundamental flaw with this theory is that Sanin Vazquez’s
unilateral actions to assert custody amounted to a declaration
that she then rejected and sought to depart from the previous
mutual arrangement. Courts routinely apply the same analysis
to determine whether a retention occurred even when the
actions evidencing retention precede the anticipated end date
of the parents’ prior agreement. See, e.g., Blackledge, 866
F.3d at 178-79; Darin, 746 F.3d at 10-11. Indeed, in the
leading case of Mozes itself, the court held that the mother
“retained” the children in the United States during a period
when the parents had agreed the children would live with her
                               17
here and before the date they had set for the family to reunite
at home in Israel. See Mozes, 239 F.3d at 1069-70 & n.5.
Summarizing the case law on retention in such circumstances,
Palencia aptly observed that “[i]n each of these cases,” just as
in this one, the “petitioning and non-custodial parent initially
assented to the child’s removal from the country of habitual
residence.” 921 F.3d at 1342. Once the parties have made clear
that they no longer agree where the child should reside—and
especially when, as here, an effort has been made to change the
custodial status quo—their prior agreement is no longer
adequate to protect custodial forum rights.

     Recognizing these authorities, Sanin Vazquez’s reply brief
pivots to a second variant of her unripeness theory. She
acknowledges that courts “may properly find that the date on
which a retention becomes wrongful [in a given jurisdiction]
can be prior to the date that both parties agreed a child can
reside in [that] jurisdiction.” Reply Br. 3. Instead, she objects
that Abou-Haidar filed his petition immediately after the
retention, rather than waiting for the agreed-upon period for the
family’s stay in Washington to elapse. In her view, the petition
here is unusual because, “[i]n all of the cases cited by Dr.
Abou-Haidar, the [Hague Convention petition] was filed and/or
the evidentiary hearing took place after the date that neither
party disputed the child could remain in the U.S., not months
prior to that date.” Id.; see also Sanin Vazquez Br. 40 (“[N]one
of the authority relied on by Dr. Abou-Haidar in the District
Court contained factual scenarios which include petitions for
return filed in respective district courts prior to the date of
agreed-upon return.”).

      We cannot credit that contention. As a descriptive matter,
it is simply incorrect. In at least two of the cases that Abou-
Haidar cites, the petition was filed before the end of an agreed-
upon sojourn. See Mozes, 239 F.3d at 1069; Blackledge, 866
                               18
F.3d at 175. And while the limits of anticipatory retention
claims may be difficult to pin down in the abstract, we have no
trouble concluding that this case involves an actual, not
anticipatory, retention. At this point, the only practical
consequence of Sanin Vazquez’s revised contention is that
Abou-Haidar would have to refile his petition in a few days,
after December 31, 2019, when Sanin Vazquez’s initial
contract with the Bank expires. Given the live dispute that
already exists between the parties and the Convention’s
command of prompt decisionmaking, delaying and duplicating
proceedings in this manner would serve no tangible benefit.
Whatever the precise contours of anticipatory retention, here
we are not resolving a hypothetical controversy.

                              IV.

     Having resolved the heart of Sanin Vazquez’s claim, we
now turn to her abbreviated challenge to the district court’s
conclusion of the second question. This question asks:
“Immediately prior to the removal or retention, in which state
was the child habitually resident?” Mozes, 239 F.3d at 1070.
Here the district court concluded, based on detailed factfinding,
that France is the child’s habitual residence. Sanin Vazquez
contends on appeal that the “factual findings made by the
District Court, when applied to the law of and interpreting the
Convention, could not possibly yield a ruling that habitual
residence was still France.” Sanin Vazquez Br. 45.

     A preliminary question is what framework we should
apply to determine the child’s habitual residence. All the
circuits to have addressed the question agree that two important
considerations are: (1) the parents’ shared intent for where the
child should reside, and (2) the child’s acclimatization to a
particular place. See, e.g., Redmond, 724 F.3d at 746 (“In
substance, all circuits—ours included—consider both parental
                              19
intent and the child’s acclimatization.”). To the extent the
circuits’ approaches diverge, they “differ[] only in their
emphasis.” Id. Under the prevailing approach, again
represented by Mozes, the primary focus is on the parent’s
shared intent. 239 F.3d at 1078-79. After ascertaining shared
intent, the court also considers acclimatization, but a child’s
acclimatization to a new place of residence overcomes contrary
parental intent only where the court “can say with confidence
that the child’s relative attachments to the two countries have
changed to the point where requiring return to the original
forum would now be tantamount to taking the child ‘out of the
family and social environment in which its life has
developed.’” Id. at 1081 (quoting Pérez-Vera Report ¶ 11).
The Sixth Circuit, and to some extent the Third Circuit, place
primary emphasis on the child’s acclimatization, treating
shared parental intent as a “back-up inquiry for children too
young or too disabled to become acclimatized.” Taglieri v.
Monasky, 907 F.3d 404, 407 (6th Cir. 2018) (en banc), cert.
granted, 139 S. Ct. 2691 (June 10, 2019) (No. 18-935); see also
Ahmed v. Ahmed, 867 F.3d 682, 688 (6th Cir. 2017); Whiting
v. Krassner, 391 F.3d 540, 550 (3d Cir. 2004); Feder v. Evans-
Feder, 63 F.3d 217, 224 (3d Cir. 1995).

      These differing emphases affect the framing of the
standard of review on appeal. Under Mozes, the habitual-
residence determination is a “mixed question of law and fact.”
239 F.3d at 1073. The factual ingredients of the inquiry, i.e.,
those “founded on the application of the fact-finding tribunal’s
experience with the mainsprings of human conduct,” are
reviewed for clear error, while legal aspects of the question,
i.e., those that require “judgment about the values that animate
legal principles,” are reviewed de novo. Id. (internal quotation
marks and citations omitted). The Sixth Circuit does not
identify any legal overlay subject to de novo review, so treats
                                  20
the habitual-residence determination as purely a “question of
fact subject to clear-error review.” Monasky, 907 F.3d at 409.

     We have no occasion to decide as a legal matter which of
these frameworks is correct because the parties agreed both
here and in the district court to application of the Mozes
framework. See Resp’t’s Proposed Findings of Fact and
Conclusions of Law 16-17 (J.A. 126-27); Pet’r’s Proposed
Findings of Fact and Conclusions of Law 12 (J.A. 141); Sanin
Vazquez Br. 43-45; Abou-Haidar Br. 33. In its amicus brief,
the government urges us instead to adopt a new standard, in
which “a child’s habitual residence under the Convention is a
factual inquiry that must take into account all relevant
circumstances in each case bearing on the ultimate question of
where the child usually or customarily lives.” U.S. Amicus Br.
13.      Under that relatively unguided, totality-of-the-
circumstances approach, “both parental intent and
acclimatization can be relevant,” but “ultimately any
determination of a child’s habitual residence must ‘remain[]
essentially fact-bound, practical, and unencumbered with rigid
rules, formulas, or presumptions.’” Id. at 20-21 (quoting
Redmond, 724 F.3d at 746). Again, given both parents’
advocacy of the Mozes framework, and the importance of
settling Convention disputes expeditiously, we see no basis to
adopt a new standard different from the one the parties
requested and briefed here and in the district court. In any
event, neither party has identified any relevant facts not
considered by the district court. 4


4
  The Supreme Court will soon clarify the appropriate standard for
habitual-residence determinations. See Monasky v. Taglieri, No. 18-
935 (argued Dec. 11, 2019). The United States there advanced the
same standard it puts forth here. Even were we to proceed to apply
the government’s preferred standard, given the particular facts of this
                                   21
     In line with the Mozes framework, we first examine the
district court’s findings regarding the parents’ shared intent,
and then its findings regarding the child’s acclimatization.

                                   A.

     The district court found, and Sanin Vazquez concedes, that
France was the family’s habitual residence before they came to
Washington, D.C. See J.A. 178; Sanin Vazquez Br. 45
(denying that the family’s habitual residence was “still France”
after the move). Under Mozes, a determination that shared
parental intent has changed requires a finding that the parties
had a “settled purpose” to establish a new habitual residence.
239 F.3d at 1074. Courts look at a variety of factors to
determine whether the parents had a shared intent to change the
child’s habitual residence, including “parental employment in
the new country of residence; the purchase of a home in the
new country and the sale of a home in the former country;
marital stability; the retention of close ties to the former
country; the storage and shipment of family possessions; the
citizenship status of the parents and children; and the stability
of the home environment in the new country of residence.”


case, the outcome would not be different. The circuit precedent to
which the government points as exemplifying its approach
recognizes that shared parental intent “may be a very important fact
in some cases,” notably in cases, like this one, where “both parents
have the right to fix the child’s place of residence.” Redmond, 724
F.3d at 744, 746-47. Moreover, the district court also considered the
child’s degree of acclimatization, and ultimately based its decision
on a variety of facts, see J.A. 181-82, including those the United
States identifies as relevant to the habitual residence inquiry, see U.S.
Amicus Br. 21. We therefore do not see the district court as running
afoul of Redmond’s caution that shared parental intent should not be
taken as a “rigid” or “uniformly applicable ‘test’ for determining
habitual residence.” 724 F.3d at 744.
                               22
Maxwell v. Maxwell, 588 F.3d 245, 252 (4th Cir. 2009). Courts
have held parents cannot establish a new habitual residence
without forsaking their existing one. A “person cannot acquire
a new habitual residence without ‘forming a settled intention to
abandon the one left behind.’” Darin, 746 F.3d at 11 (quoting
Mozes, 239 F.3d at 1075).

     Crucially, Mozes tells us that “[w]hether there is a settled
intention to abandon a prior habitual residence is a question of
fact as to which we defer to the district court.” 239 F.3d at
1075-76. Here, the district court canvassed all of the record
evidence and found that the parties intended to remain in
Washington, D.C. for the eighteen months of Sanin Vazquez’s
initial contract, but that any plans to stay beyond that period
were “aspirational and contingent.” J.A. 178. Looking at a
variety of factors, the court concluded that the “parties did not
leave France in a manner that would suggest a shared intent to
relocate indefinitely to the United States.” J.A. 153; see also
J.A. 179. The district court’s detailed, record-based factual
findings fully support that determination. The court found that
the couple kept their French jobs and stored their personal
belongings in France, Sanin Vazquez maintained her French
pension, and the couple did not have any going-away party or
other social event such as one might expect had they intended
a permanent departure from France. J.A. 179. Moreover, the
couple and their daughter—all of whom were EU citizens with
rights to remain in France indefinitely—had no prior
connection to the United States, obtained only temporary visas
to live here, and rented rather than bought property in
Washington, D.C. J.A. 179-80 & n.4. Finally, Abou-Haidar
continued to spend nearly half of each month living and
working in France and made no effort or plans to obtain an
American medical license. J.A. 179.
                               23
     On appeal, Sanin Vazquez has not articulated why any of
these factual findings is clearly erroneous. She highlights
several other facts relevant to an intent to shift the family’s
habitual residence to the United States, including the parties’
initial attempt to buy a home in Washington, the fact that they
rented out their Barcelona apartment for a three-year term, and
a series of text messages from Abou-Haidar referring to the
possibility of a stay of up to three years in the United States.
J.A. 55, 64-68, 248-49, 278, 282, 320. But the district court
took those facts into account. It determined that the parties
considered buying a home in Washington primarily as an
investment, see J.A. 179 n.4, and reasonably rejected Sanin
Vazquez’s contention that her renegotiated Bank contract
would automatically renew after 18 months to create a default
three-year stay in Washington, see J.A. 167. Sanin Vazquez
also claims that the district court erred in crediting Abou-
Haidar’s testimony and the corroborating testimony of his
friends, rather than the testimony of her friends and family, as
to the parties’ stated intentions upon departure from France.
Sanin Vazquez Br. 45-46. But our review is at its most
deferential when it comes to reexamining the district court’s
credibility determinations. See, e.g., Maxwell, 588 F.3d at 253.

     To the extent that Sanin Vazquez suggests that the district
court made a mistake of law, her primary argument is that the
district court “erroneously imposed a requirement that the
parties supplant the former habitual residence of Paris with
Washington, D.C., in order to effectively abandon Paris.”
Sanin Vazquez Br. 44. Sanin Vazquez herself does not take a
consistent position in her briefing as to whether she believes
the family has simply abandoned France, id. at 43, abandoned
France in favor of habitual residence in the United States, id. at
45, or abandoned France en route to establishing habitual
residence in Uruguay, id. at 44. Mozes recognizes a conceptual
difference between abandoning a habitual residence and
                                 24
establishing a new one: a person can abandon a habitual
residence “in a single day if he or she leaves it with a settled
intention not to return to it,” but an “appreciable period of time
and a settled intention will be necessary to enable him or her to
become” habitually resident in a new country. Mozes, 239 F.3d
at 1074-75 (internal quotation marks and citation omitted). The
district court explicitly acknowledged this conceptual
difference, and held only that the parents did not have a settled
intention to abandon France, regardless of their intentions with
respect to Washington, D.C. J.A. 154 n.3. The district court’s
factual finding of the absence of settled intention to abandon
France suffices to support its habitual-residence holding. We
see no legal error in its analysis of the point. 5

                                 B.

     The second inquiry, subsidiary under the parties’
stipulated Mozes framework, is the child’s acclimatization to
the new country. “Evidence of acclimatization is not enough
to establish a child’s habitual residence in a new country when
contrary parental intent exists.” Darin, 746 F.3d at 12 (citing
Mozes, 239 F.3d at 1078-79). Mozes further counsels that
courts should “be slow to infer from [a child’s contacts] that an
earlier habitual residence has been abandoned” in the absence

5
  Sanin Vazquez also mentions the French Central Authority’s
rejection of Abou-Haidar’s request for its assistance. See Sanin
Vazquez Br. 12-13. We agree with the United States that no
deference to that action is due because the Convention assigns the
legal and factual determinations relevant to a claim of wrongful
retention (or removal) to the courts of the Contracting States, not to
the Central Authorities. See Special Commission on the Practical
Operation of the 1980 and 1996 Hague Conventions, Conclusions
and Recommendations 2 (¶ 13) (June 1-10, 2011),
https://assets.hcch.net/upload/wop/concl28sc6_e.pdf; U.S. Amicus
Br. 29-33.
                                25
of shared parental intent to do so. 239 F.3d at 1079. Courts
view a variety of factors as relevant to acclimatization,
including “school enrollment, participation in social activities,
the length of stay in the relative countries, and the child’s age.”
Maxwell, 588 F.3d at 254.

     Here, Sanin Vazquez has not identified any error in the
district court’s findings regarding the child’s acclimatization.
The district court recognized that the child had adjusted to a
new school, made friends, and participated in extracurricular
activities in the ten months she spent in the United States prior
to the retention in May 2019. J.A. 182. But, until the sojourn
in Washington, the child’s life was based almost entirely in
Paris: her parents married there, she was born there, and she
attended nursery school there.

      Sanin Vazquez has not argued that the district court
committed any legal error in applying the Mozes framework to
its findings relating to the parents’ shared intentions and the
child’s acclimatization. She does not urge us to adopt any other
court’s approach (nor the approach the government describes).
And she does not argue that any of the district court’s factual
findings, including its findings supporting its shared parental
intent determination, were clearly erroneous. In these
circumstances, the district court reasonably determined that
“[e]vidence of acclimatization over such a short period of time
for such a young child is not enough to overcome the parties’
lack of intent to abandon France,” or any of the other factual
indicia showing that France was their daughter’s habitual
residence. J.A. 182.

                            *   *    *
    We conclude that Sanin Vazquez’s arguments regarding
the date of retention and the child’s habitual residence lack
merit. Because the parties chose the Mozes framework, and
                             26
Sanin Vazquez has not challenged the district court’s findings
under the remaining questions or asserted any defenses, we
affirm the district court’s judgment granting Abou-Haidar’s
petition for return.

                                                  So ordered.
