Marriage contracts and international wills: planning ahead, with the IDFP (2023-2026)

Between 2023 and 2026, I led three sessions on international matrimonial and estate planning for the Institut du droit de la famille et du patrimoine (IDFP), a French family and estate law institute: two practical private international law workshops in 2023, with Maxime Eppler and Joana Silveira, then a “PIL Lunch” (Déjeuner du DIP) webinar on April 17, 2026, with Morgane Le Gall and Thomas Dyall, a notary. Here are the key takeaways, along with the slides from the latest session.

Why plan ahead?

A couple who marries abroad, moves abroad or combines two nationalities and plans nothing is exposed to a series of foreseeable disputes: where their habitual residence was, which court has jurisdiction, which law applies; parallel proceedings, each spouse seizing the courts of their own country; lis pendens rules with known limits before courts that look for the most appropriate forum; for spouses married between 1992 and 2019, an automatic change in the law governing their matrimonial property regime (régime matrimonial); and uncertainty as to whether a will is valid from one country to another.

The tools exist: choice-of-law and choice-of-court clauses, an international marriage contract, a will, and even a clause requiring an amicable attempt before going to court. So do their limits: international public policy, the best interests of the child, the court’s assessment in equity, and the recognition of agreements abroad. Hence the need to work as a pair, lawyer and notary, and with a colleague in each country concerned.

The common thread: a Franco-British couple seeking protection

In 2026, the case study featured a French national living in London for eight years and his future wife, an American who may one day move back to New York. They hold a house in London through a trust and an apartment in Paris through a French real estate company (société civile immobilière). They will marry in Paris and want to settle now the consequences of a possible divorce, in a separate-property spirit, and then organize the transfer of their estate.

Twenty questions guided participants: ten about their marriage, ten about their estate. A French marriage contract, an English prenuptial agreement, both or neither? Which law, which court? A French, English or international will? Can the children be deprived of their forced share (réserve héréditaire), can a trust be used, can taxes be reduced?

One marriage contract, drafted to be recognized

The slides are clear: signing both a French marriage contract and a prenuptial agreement is strongly discouraged, as it may undermine the first. The country of drafting is chosen according to the future spouses’ residence, their nationalities, the location of their assets and the place of the marriage. Back in 2023, the Franco-Brazilian case already questioned the practice of “mirror” contracts signed in each country.

Absent a choice, English law would govern the divorce, the property regime and support here. The future spouses may choose French law for all three, and the court for support and the property regime, but not for the divorce itself. The French marriage contract has its limits: it cannot settle the consequences of divorce in advance, and the spouses cannot waive their future right to a compensatory allowance (prestation compensatoire) before divorce proceedings begin. To be recognized in England, it requires that each spouse be advised by their own lawyer and that each fully disclose their assets and income. Specific clauses support it: intent to be recognized abroad, understanding of the language, separate advice, financial disclosure, fairness.

The will: form, governing law and forced share

The 1961 Hague Convention and the 1973 Washington Convention govern the formal validity of a will, not the recognition of its content: the draft should be reviewed by a lawyer or notary in each country concerned. A handwritten will may be written in any language, provided its author understands it; a notarial will may be received with an interpreter when the testator does not speak French (art. 972, Civil Code). It is best registered with the French central register of wills (Fichier central des dispositions de dernières volontés).

Absent a choice, the estate is governed by the law of the last habitual residence, with a possible renvoi when the deceased lived in the United Kingdom, whose law distinguishes movable from immovable property. The choice of law is limited to the law of nationality. As for the forced share, a foreign law that ignores it is not in itself contrary to international public policy, but the French law of August 24, 2021 created a compensatory levy right on assets located in France.

Sessions

• April 17, 2026“PIL Lunch” webinar (12-2 p.m.), with Morgane Le Gall and Thomas Dyall, a notary: the Franco-British case, ten questions on the property regime and ten on the estate, and model international marriage contract and international will.
• November 15, 2023Workshop no. 4 of the second (expert-level) cycle of the practical PIL workshops, at the Paris bar’s Maison du Barreau, with Maxime Eppler and Joana Silveira: a Franco-Brazilian case and the issue of two “mirror” marriage contracts.
• September 22, 2023Workshop no. 4 of the practical PIL workshops, at the Maison du Barreau, with Maxime Eppler and Joana Silveira: a same-sex Franco-Italian couple preparing their marriage and estate.

Key takeaways

1. 1Plan before the wedding or the move abroadThat is when choosing the law and the court is still possible and useful.
2. 2One contract onlyMarriage contract or prenuptial agreement: signing two may undermine the first.
3. 3Choose the law, and the court where allowedDivorce, property regime, support: one law and one court, except for the divorce itself.
4. 4Prepare for recognition abroadSeparate advice for each spouse, full financial disclosure, tailored clauses.
5. 5Coordinate willsFormal validity, language, governing law and forced share must be checked country by country.
6. 6Work as a pairLawyer and notary, at home and abroad: international planning is a team effort.

Training excerpts

General information. This account of a talk reflects only my personal opinion and is not legal advice. The cases mentioned are fictional, or inspired by real cases, modified and anonymized.