Americans usually start estate planning with a simple assumption: write a will, name the beneficiaries, and your wishes control. That instinct works reasonably well in much of the United States, where children can often be disinherited and the main statutory protection tends to focus on the surviving spouse. France starts from a very different premise. Under French succession law, children may have a protected share of the estate that cannot simply be signed away.
That protected share is the réserve héréditaire. If you are an American who lives in France, owns French real estate, has children in France, or is married to a French spouse, this concept is one of the first things you need to understand before you rely on a US-style will. Bordure's Inheritance & Estate Planning Guide covers the broader framework. This article focuses on the question many Americans actually type into Google: what happens when French forced heirship collides with US estate planning?
Quick answer
If French succession law applies, you cannot assume you are free to leave everything to a spouse, stepchild, charity, or trust. The number of children usually determines how much of the estate is reserved for them, and only the remaining portion can be freely directed elsewhere. A will choosing US law may help in some France-US cases, but it does not solve every problem and it does not eliminate French tax or French asset-level risk by itself.
What réserve héréditaire actually means
In plain English, the reserve is the part of an estate that French law protects for children. The balance is the quotité disponible, the portion you are free to allocate by will, gift, or planning structure. The reserve is not a minor technicality. It is a core design feature of the French system.
| Children | Reserved share | Freely disposable share |
|---|---|---|
| One child | One-half of the estate | One-half |
| Two children | Two-thirds of the estate | One-third |
| Three or more children | Three-quarters of the estate | One-quarter |
That table is the practical starting point for Americans. If you have two children, for example, French law normally protects two-thirds of the estate for them. You may still have planning tools around the remaining third, around matrimonial property, and around how the spouse receives rights over the estate. But you are not operating in a system of full testamentary freedom.
If gifts or will provisions go too far, reserved heirs can bring an action en réduction to claw back the excess. That remedy is one reason Americans get into trouble when they assume a foreign will controls automatically. A document can be validly signed and still leave behind a French reserve problem.
Why Americans often miss the issue
In most US states, the default planning instinct is spouse-first: leave everything to the surviving spouse, then to the children later. Children usually do not have an automatic guaranteed share in the way French law gives them one. That difference creates the most common Franco-American misunderstanding in estate planning.
Americans also tend to underestimate how much French succession law cares about family structure. Whether all children are from the same marriage, whether there are children from a prior relationship, and whether the couple is actually married all matter. A PACS or unmarried-partner situation needs its own analysis, which is one reason Bordure's Legal Guide is worth reviewing alongside inheritance planning.
Common mistake
Americans often focus on tax first and succession law second. In France, the order should usually be reversed. First ask who is legally entitled to what. Only after that should you model the tax cost of the structure.
When French succession law can apply to an American
The next question is not whether you are American. It is which law governs the succession. Under the EU Succession Regulation commonly called Brussels IV, the default rule generally points to the law of the deceased's last habitual residence. For many Americans who have genuinely settled in France, that means French succession law is the default starting point, even if the person kept US nationality and even if some assets are abroad.
That does not mean every US probate court or every US financial institution will behave identically. Local asset-transfer rules still matter. But from the French notarial side, habitual residence is usually the central connecting factor. If you live in France year round, your planning should assume French succession analysis is in play unless a specialist confirms otherwise.
Americans who remain habitually resident in the US but own a French apartment or holiday house also need to be careful. Cross-border estates are not judged by nationality alone, and French assets can still drag French succession mechanics into the conversation.
Can an American choose US law instead?
Often, yes. Brussels IV generally allows a person to choose the law of their nationality to govern the succession as a whole, and that rule is not limited to EU nationals. In practical terms, an American who writes a properly drafted will can often elect US law as the law of nationality and move away from the French default rule, with separate advice needed on how that interacts with state-law concepts inside the US system.
But Americans should not over-read that option. A US-law election is not a magic eraser. It may improve testamentary freedom, but it does not change the need for a valid will in the right format, it does not settle French inheritance tax, and it does not guarantee that every French-policy issue disappears where French assets and French heirs remain involved.
The most important modern warning is the 2021 French reform to Article 913 of the Code civil. In certain international estates, where a foreign law applies and offers no child-protective reserve, certain children can claim a compensatory levy against assets located in France so they recover the reserved rights French law would have given them. This is exactly why Americans should stop thinking of a US-law election as an automatic workaround.
The real planning question is not "Can I elect US law?" It is "If I elect US law, what French exposure still remains for the estate, the spouse, and the children?"
What the surviving spouse can realistically expect
Another American misconception is that the spouse automatically comes first under French law. The answer is more nuanced. If the deceased leaves only children common to the marriage, the surviving spouse generally has a statutory choice between one-quarter in full ownership and a life interest (usufruit) over the whole estate. If the deceased leaves children from another relationship, the spouse is generally limited by default to one-quarter in full ownership unless stronger planning was put in place in advance.
This is why blended-family estates are high-risk. A surviving American spouse may expect to keep control of the French home, while adult children from an earlier relationship expect immediate ownership rights. Both sides can be acting in good faith and still collide with a brutal degree of legal and emotional force.
If there are no descendants, the position is different and often more flexible. In that case the surviving spouse is much better protected, and the child-reserve issue may disappear entirely. That is one reason child-free couples should not copy estate plans written for families with children. That household reality also affects the annual admin stack, which is why many couples pair this planning with Bordure's US tax filing guide for spouses once they start building a life in France together.
Three real-world examples Americans should test
Example 1: Married couple in Paris with two common children
A US citizen lives in Paris with a French spouse and two children. The American wants a will leaving everything outright to the spouse. If French succession law governs, two-thirds of the estate is usually reserved for the children. The surviving spouse may still have important rights, but "everything to my spouse" is not the baseline outcome.
Example 2: American chooses New York law for a French apartment
An American in France signs a will electing New York law and owns an apartment in Lyon. One child lives in France. The election may still be useful, but it should be reviewed together with the French compensatory-levy rules. If the chosen foreign law offers no child-protective reserve, French-situs assets may remain exposed to a claim from a protected child.
Example 3: Second marriage, children from a prior relationship
A widowed American remarries in France and wants the new spouse to stay secure in the home for life, with children inheriting later. This is exactly the sort of plan that needs bespoke French drafting. The default statutory outcome may be too weak for the spouse and too conflict-prone for the children. Relying on a generic US will is how families end up fighting through indivision, occupancy rights, and forced-sale pressure after death.
What cross-border estate planning should look like in practice
Good France-US estate planning is usually not about one perfect document. It is about coordinated decisions across succession law, marital property, tax, and asset location. If your life touches both countries, these are the practical steps worth taking:
- Identify your likely habitual residence and which country's law currently governs the succession by default.
- Review every existing will, trust, beneficiary designation, and marital agreement for France compatibility instead of assuming they already fit together.
- Model the family fact pattern honestly: common children, stepchildren, prior marriages, and vulnerable heirs all change the analysis.
- Separate succession questions from tax questions. Inheritance tax answers do not tell you who is legally entitled to inherit.
- Check every French asset individually, especially real estate, for exposure if a child later asserts reserve rights.
- Revisit the plan after a move, marriage, divorce, birth, property purchase, or change in country of residence.
If you also need the broader France-US framework, use the Inheritance Guidefor wills, tax, assurance-vie, and gifting context. If the estate includes a French home or a move to France is part of the story, Bordure's Daily Life Guide is useful for the ownership and household-admin angle that often sits behind the estate plan. If the move itself is still in flight, use the spouse visa guide alongside this article so your residence timeline and your succession-law assumptions stay aligned.
Practical planning tip
Do not ask one lawyer, "Is my US will valid in France?" and stop there. Ask a better question: "What result will this plan produce for my spouse, my children, my French assets, and my tax exposure if I die next year?"
If you want the shorter paid version before you start briefing professionals, the Bordure Premium Handbook is the practical companion. It is built for French-American couples who want the decision order, the questions to ask, and the recurring pitfalls in one place before they spend more time or money.
Bottom line
Réserve héréditaire is the part of French inheritance law Americans cannot afford to treat as background noise. If France is your habitual residence, if your heirs are in France, or if your wealth includes French assets, the reserve can determine whether your estate plan actually works. A US-law election may still be useful, but it is a planning tool, not a guarantee.
The safe mindset is simple: do not ask whether your US documents exist, ask whether they produce the right French result. That is the difference between having a plan and merely having paperwork.