Separation is hard enough without a border running through the middle of it. When a British parent living in France splits from the other parent, three questions arrive at once: which court decides where the children live, whether one parent can move back to the United Kingdom with them, and what happens if a child is taken across the Channel without agreement. Since Brexit, the answers no longer sit in one European rulebook. The United Kingdom is a third state for family law, so a British family in France now lives under a combination of French domestic law, the 1980 Hague Convention on child abduction, and the 1996 Hague Convention on parental responsibility. This article explains, step by step, how the French family judge fixes custody, how a lawful relocation is organised, how the emergency return procedure works when a move is unlawful, and how an English court order is given effect in France — with the exact texts and recent court decisions that decide real cases.

I. Which court decides custody when a British-French family splits after Brexit

Before Brexit, one European instrument — Brussels II bis — allocated custody jurisdiction between France and the United Kingdom almost automatically. That instrument no longer binds the United Kingdom. Between EU Member States, its successor, Regulation (EU) 2019/1111, known as Brussels II ter (the Regulation itself), now governs jurisdiction, recognition and enforcement. But as between France and England, the case is decided under French rules of international jurisdiction combined with the Convention of 19 October 1996 on jurisdiction, applicable law, recognition and enforcement in matters of parental responsibility (official text on the Hague Conference site), to which both France and the United Kingdom are parties. In practice, this means the decisive question is almost always the same: where is the child’s habitual residence?

A. Habitual residence: the test that fixes jurisdiction and the applicable law

Habitual residence (résidence habituelle, the place where the child actually lives day to day) is a question of fact, not of paperwork. The judge looks at where the child goes to school, where the doctors, clubs and friends are, how long the family has been settled, and where the centre of the child’s life genuinely lies. A British passport, an English birth certificate or a house in Kent does not move habitual residence on its own. If the children live, go to school and have their settled life in Lyon, Bordeaux or Paris, their habitual residence is France — and the French courts take the case.

On the French side, the competent judge is the juge aux affaires familiales (the family court judge, often shortened to JAF), sitting within the tribunal judiciaire (the ordinary civil court of first instance) of the place where the children live. The official service-public guidance on applying to that judge sets out the procedure and the forms (service-public.fr: applying to the family judge), and its companion page explains how parental authority works when parents separate (service-public.fr: parental authority on separation).

Habitual residence does more than fix the court: it largely fixes the law that says who holds parental responsibility in the first place. The Court of Cassation recalled the mechanism in a return case decided on 12 June 2025 (Cass. 1re civ., 12 June 2025, no. 24-17.787): “Selon l’article 16, § 1, de ladite Convention, l’attribution ou l’extinction de plein droit d’une responsabilité parentale, sans intervention d’une autorité judiciaire ou administrative, est régie par la loi de l’Etat de la résidence habituelle de l’enfant”, and “selon l’article 16, § 3, la responsabilité parentale existant selon la loi de l’Etat de la résidence habituelle de l’enfant subsiste après le changement de cette résidence habituelle dans un autre Etat.” In plain terms, the law of the country where the child habitually lives decides who holds parental responsibility by operation of law, and that responsibility survives a later move. A British reader should note the consequence: if the children are habitually resident in France, it is French law that says whether both parents share parental authority, even if the family previously lived under English arrangements.

Under French law itself, the starting point strongly favours both parents. Parental authority (autorité parentale, the bundle of rights and duties over the child’s safety, health, education and development) is defined by Article 371-1 of the Civil Code: “L’autorité parentale est un ensemble de droits et de devoirs ayant pour finalité l’intérêt de l’enfant.” And Article 373-2 of the Civil Code adds the principle that separation changes nothing by itself: “La séparation des parents est sans incidence sur les règles de dévolution de l’exercice de l’autorité parentale.” Joint exercise remains the default after a split; taking it away from one parent requires a court order justified by the child’s interests. So a British mother or father in France does not lose a say over schooling, medical treatment or travel simply because the couple separated or because one of them is the foreign parent. The official overview of joint parental authority confirms the same default (service-public.fr: exercise of parental authority).

Two practical warnings follow from this. First, habitual residence can shift silently. A “temporary” stay in England that stretches over school terms, with the child enrolled locally and integrated, can become the new habitual residence — which then changes which court decides and which law attributes responsibility. Second, the parent who plans a move should never engineer facts on the ground and hope the court catches up. French judges treat unilateral fait accompli moves severely, and the emergency return procedure described in Part II exists precisely to undo them. The lawful route is always a joint agreement or a judge’s authorisation before the move.

B. What the French family judge actually orders: home, contact, money and the child’s own voice

When parents cannot agree, the family judge builds the whole custody package around one compass: the child’s best interests (intérêt de l’enfant). Article 373-2-11 of the Civil Code tells the judge what to weigh: “Lorsqu’il se prononce sur les modalités d’exercice de l’autorité parentale, le juge prend notamment en considération” six factors — the parents’ previous practice and any earlier agreements; the feelings expressed by the child under the hearing procedure; each parent’s ability to assume their duties and respect the other’s rights; any expert assessments with regard to the child’s age; social inquiry reports; and any physical or psychological pressure or violence by one parent against the other. For a British litigant used to the English welfare checklist, this list will feel familiar in substance, but its application is French: written evidence, school and medical records, and the social inquiry (enquête sociale) carry heavy weight.

On the child’s home, Article 373-2-9 of the Civil Code provides that “la résidence de l’enfant peut être fixée en alternance au domicile de chacun des parents ou au domicile de l’un d’eux.” Shared residence (résidence en alternance, broadly the French equivalent of shared care) is available, and the judge can order it on a trial basis even where the parents disagree — but it is never automatic. Distance is the great practical killer of alternance: a week-about arrangement between Paris and London is not workable for a school-age child, and judges say so plainly. Where the child’s home is fixed with one parent, the other parent receives contact rights (droit de visite et d’hébergement, literally the right to visit and to have the child stay over), which the official guidance details with practical examples (service-public.fr: contact rights on separation). For cross-Channel families, the order should spell out the school-holiday calendar with precision — which half of each holiday, who books and pays for the Eurostar or flights, where handovers happen, and daily video contact — because vague orders generate the enforcement disputes of the following year.

Money follows the same child-centred logic. Article 371-2 of the Civil Code states that “Chacun des parents contribue à l’entretien et à l’éducation des enfants à proportion de ses ressources, de celles de l’autre parent, ainsi que des besoins de l’enfant.” Child maintenance (contribution à l’entretien et à l’éducation) is proportionate to each parent’s means and the child’s needs, and it survives even the withdrawal of parental authority or the child’s majority in appropriate cases. Sterling earnings do not complicate the principle, though the judge will want reliable evidence of the English income — payslips, P60s and tax returns, converted sensibly — and the order should state the currency, the payment channel and indexation so that exchange-rate drift does not become a yearly grievance. Parents who agree the figures privately should still have their agreement homologated (formally approved) by the judge, because only then does it become enforceable with public force if payments stop.

The child is not a spectator in this process. Article 388-1 of the Civil Code provides that “Dans toute procédure le concernant, le mineur capable de discernement peut, sans préjudice des dispositions prévoyant son intervention ou son consentement, être entendu par le juge ou, lorsque son intérêt le commande, par la personne désignée par le juge à cet effet. Cette audition est de droit lorsque le mineur en fait la demande.” The hearing (audition) is therefore a right when the child asks for it, and the Court of Cassation enforces it strictly: on 16 February 2022 it quashed an appeal decision that had fixed a child’s residence without hearing her and without giving reasons for the refusal (Cass. 1re civ., 16 February 2022, no. 21-23.087), recalling that “dans toute procédure le concernant, le mineur capable de discernement peut être entendu par le juge et cette audition est de droit lorsqu’il en fait la demande.” British parents should understand both the strength and the limit here: the child’s words matter and can tip a close case, but the hearing never makes the child a party and never transfers the decision to the child. The judge listens, then decides.

Finally, relocation itself has its own statutory track. Article 373-2 of the Civil Code requires that “Tout changement de résidence de l’un des parents, dès lors qu’il modifie les modalités d’exercice de l’autorité parentale, doit faire l’objet d’une information préalable et en temps utile de l’autre parent.” A move from France to England that changes how parental authority works in practice — which it almost always does — must therefore be notified to the other parent in advance and in good time. “En cas de désaccord, le parent le plus diligent saisit le juge aux affaires familiales qui statue selon ce qu’exige l’intérêt de l’enfant.” The parent who acts first seises the judge, who rules by the child’s interests; and the same article directs that “Le juge répartit les frais de déplacement et ajuste en conséquence le montant de la contribution à l’entretien et à l’éducation de l’enfant.” Travel costs are shared out and maintenance adjusted accordingly. In other words, the parent who wants to relocate must warn, must negotiate, and — failing agreement — must win the judge’s authorisation before moving. A quiet departure with the children and a text message from St Pancras is not a relocation plan; it is the fact pattern of an abduction case.

Readers dealing with the financial and property side of the same split — which court takes the divorce, which law divides the house and the pension — will find the companion analysis on the firm’s divorce pages (British divorce in France: court, law and enforcement), which this custody guide complements rather than repeats. For the custody, contact and return fundamentals applied in recent cases, see also the firm’s dedicated guide to child custody, residence and contact orders, enforcing an English order and bringing a child back.

II. When a parent takes the child across the Channel without agreement

Every year, some separations turn into unilateral moves: one parent boards a ferry or a train with the children and announces the new arrangement afterwards. French law draws a sharp line here. A move agreed with the other holder of parental authority, or authorised by the family judge under Article 373-2, is a relocation to be organised. A move without either is potentially a wrongful removal, and it triggers a fast-track international procedure whose only question is where the child should be while the custody courts do their work — not who should ultimately win custody.

A. Wrongful removal, the Hague return case and the defences that actually work

The 1980 Hague Convention on the Civil Aspects of International Child Abduction (official full text) applies fully between France and the United Kingdom. Its core test is set by Article 3: a removal or retention counts as wrongful where it breaches rights of custody attributed by the law of the State where the child was habitually resident just before the move, provided those rights were actually being exercised. The Court of Cassation restated the French-law version of that test on 12 June 2025 (Cass. 1re civ., 12 June 2025, no. 24-17.787): “Selon l’article 3 b) de la Convention de La Haye du 25 octobre 1980 sur les aspects civils de l’enlèvement international d’enfants, le déplacement ou le non-retour d’un enfant est considéré comme illicite lorsqu’il a eu lieu en violation d’un droit de garde, attribué par le droit de l’Etat dans lequel l’enfant avait sa résidence habituelle immédiatement avant son déplacement ou son non-retour.” And Article 5 gives custody its broad Convention meaning: “Selon l’article 5 a) de la même Convention, le droit de garde, au sens de ce texte, comprend le droit portant sur les soins de la personne de l’enfant et, en particulier, celui de décider de son lieu de résidence.” Joint parental authority under French law therefore counts as custody: either holder’s right to decide where the child lives is enough to make a unilateral move wrongful.

A second decision, given on 30 April 2025, shows how the test bites where parents share authority (Cass. 1re civ., 30 April 2025, no. 24-20.497): “Selon l’article 3 de la Convention de La Haye du 25 octobre 1980 sur les aspects civils de l’enlèvement international d’enfants, est illicite tout déplacement d’un enfant fait en violation du droit de garde exercé effectivement et attribué à une personne par le droit ou le juge de l’Etat dans lequel l’enfant avait sa résidence habituelle avant son déplacement.” The court approved the appeal judges’ finding that the father, who jointly held parental authority and had an access calendar fixed by the child-protection authority, was genuinely exercising his custody rights — so the mother’s unilateral departure with the children was wrongful and their immediate return was ordered. The lesson for British parents is direct: where both parents share autorité parentale, neither may decide alone to move the children from France to England. Consent or a court order first; the ferry second.

Once wrongfulness is established, the Convention’s rule is speed. Article 12 provides that where proceedings start within a year of the removal, “the authority concerned shall order the return of the child forthwith”; even after a year, return remains the rule “unless it is demonstrated that the child is now settled in its new environment.” In France, the practical channel runs through the Central Authority and the public prosecutor: the left-behind parent applies (from England, via the UK Central Authority guidance on international parental child abduction), the French Central Authority transmits the file, and the procureur de la République (the public prosecutor) brings the return case before the family judge — exactly as happened in the June 2025 case, where the prosecutor assigned the mother before the Lille family judge. The return hearing is summary and focused: habitual residence, custody rights, effective exercise, and the defences. It does not re-decide custody.

The defences are narrow and evidence-hungry, and Article 13 lists them exactly: the opponent of return must establish either that custody “was not actually exercising the custody rights at the time of removal or retention, or had consented to or subsequently acquiesced in the removal or retention”, or that “there is a grave risk that his or her return would expose the child to physical or psychological harm or otherwise place the child in an intolerable situation.” A further paragraph lets the judge refuse return where “the child objects to being returned and has attained an age and degree of maturity at which it is appropriate to take account of its views.” Three cautions matter. First, non-exercise must be proved with documents, not asserted: months of uninvolved parenting evidenced by school and medical records. Second, the grave-risk exception is not a re-run of the custody debate and not a commentary on the other country’s family courts; it needs concrete, current evidence of harm or intolerability, ideally with protective measures examined on both sides. Third, the child’s objection counts only at a sufficient age and maturity, assessed carefully — the same discernment logic as the Article 388-1 hearing, but operating as a shield against return rather than as one factor among many. Arguments that the child prefers English schools, speaks better English, or would enjoy a bigger house in Surrey do not meet any of these tests.

From the English side of the same situation, the British government’s guidance tells a left-behind parent in the UK to contact the UK Central Authority promptly, to consider a Port Alert through the police where imminent travel is feared, and to seek specialist advice without delay (gov.uk: international parental child abduction). The charity Reunite, referenced in that guidance, supports families through the process. The message is the same on both shores: hours matter, because delay feeds the “settled” argument and complicates recovery.

B. Enforcing an English order in France and challenging a refusal

Suppose the custody order already exists — made in London before the family moved, or made by an English court after a lawful relocation — and it now needs to work in France: school enrolment, a bailiff’s assistance, a penalty for non-compliance. Since Brexit, English family orders no longer circulate in France automatically. They must pass through exequatur (the court procedure that declares a foreign judgment enforceable on French soil). The gateway text is short and clear. Article 509 of the Code of Civil Procedure provides: “Les jugements rendus par les tribunaux étrangers et les actes reçus par les officiers étrangers sont exécutoires sur le territoire de la République de la manière et dans les cas prévus par la loi.” The application goes to the tribunal judiciaire, with representation by a French lawyer, a certified translation of the English order, and proof that it is final and enforceable in England. Until exequatur is granted, the English order has no coercive force in France: no penalty payments, no compulsory enforcement, no registration against assets.

Once the English order is declared enforceable — or where a French order already governs — French enforcement tools are muscular. Article 373-2-6 of the Civil Code lets the family judge back any custody arrangement with an astreinte (a daily penalty payment for each day of non-compliance), and even attach a penalty to another judge’s order or to a recorded parental agreement. The same article allows the judge to “ordonner l’interdiction de sortie de l’enfant du territoire français sans l’autorisation des deux parents” — an exit ban (interdiction de sortie du territoire, IST) entered on the wanted-persons file by the prosecutor — which border police then enforce at airports, ports and stations. And where a parent deliberately and repeatedly obstructs a custody title, the judge may impose a civil fine: “le condamner au paiement d’une amende civile d’un montant qui ne peut excéder 10 000 €.” These are the levers that make a cross-Channel contact schedule real: the penalty-funded return ticket, so to speak.

Refusals and setbacks have their own remedies, and each has a clock. If the family judge refuses a relocation, refuses to modify residence, or declines exequatur, the ordinary route is an appeal (appel) to the cour d’appel, which re-hears the facts — but strict time limits run from notification of the judgment, so the disappointed parent must move within weeks, not months. Urgent dangers have an urgent route: where a child faces an imminent unlawful departure, the judge can be seised in emergency proceedings for an exit ban or provisional measures before the main case is heard. And custody orders are never frozen forever: on proof of genuinely new facts (éléments nouveaux) — a completed move, a teenager’s settled objection, a documented breakdown of contact — either parent can ask the family judge to revisit residence, contact and maintenance. What never works is self-help: withholding the child after a holiday, cancelling contact unilaterally, or ignoring an order while “waiting for England to decide” converts a sympathetic custody case into an enforcement case with penalties attached, and the obstructing parent pays for that conversion twice — in costs and in credibility.

One last asymmetry deserves a plain statement. An English judge and a French judge can each be seised about the same children at the same time, and since Brexit no European lis pendens rule forces one to yield automatically. Parallel proceedings are therefore possible and expensive. The antidote is procedural discipline: raise the foreign proceedings early and transparently before each court, seek a stay where one forum is plainly the children’s home, and avoid asking either judge to contradict a subsisting order of the other without first pursuing recognition. Courts on both sides of the Channel penalise tactical silence far more than they reward it.

Conclusion

A British family splitting up in France lives under French custody law from the moment the children’s habitual residence is French: joint parental authority is the default, the family judge weighs the six statutory factors with the child’s own voice heard as of right, and any move to England needs the other parent’s agreement or the judge’s prior authorisation, with travel costs shared and maintenance adjusted. A unilateral departure reverses the momentum: the 1980 Hague Convention orders a swift return to the country of habitual residence, subject only to narrow, evidence-heavy defences, and English orders need French exequatur before they bite. The parents who fare best are the ones who document everything — schooling, caregiving, involvement — notify before moving, apply before travelling, and treat the other parent’s rights as the court’s starting point rather than an obstacle. In cross-Channel custody disputes, procedure is not the sideshow. It is the case.