Many people with a French parent or grandparent assume that French citizenship by descent is simply waiting for them, and that they can claim it whenever they decide the time is right. In a great many cases they are correct, because French nationality passes from parent to child without any limit on the number of generations, so that a child born in New York, Buenos Aires or Montreal to a French father or mother is French from the moment of birth, whether or not anyone has ever filed a single document.
There is, however, a rule that regularly takes families by surprise and can mean that French citizenship has been lost without anyone realising it. Where a family has lived outside France for more than fifty years and nobody in the line has behaved, in the eyes of the French State, as a French citizen during that time, French law treats the connection as having lapsed. This is known as désuétude, often described in English as the 50-year rule or loss of French nationality through non-use, and once it applies the French courts will not allow you to prove your French ancestry, however complete and well documented your family records may be.
This article explains, in plain terms, how the 50-year rule works, how the French courts apply it today, how it affects Americans and other descendants of French emigrants, and how lost French citizenship can sometimes be reclaimed.
What is désuétude? The 50-year rule for French nationality by descent
The rule is set out in article 30-3 of the French Civil Code, read together with article 23-6. It goes back to the nationality code of 1945, and its original aim was to stop French nationality by descent being passed down indefinitely to the descendants of French emigrants who had long since lost any real connection with France.
For désuétude to apply, three conditions must all be met at the same time:
- You live, or have lived, outside France.
- The ancestors through whom you inherit French nationality remained settled abroad for more than fifty years.
- Neither you nor the parent through whom you claim French citizenship had what French law calls “possession d’état de Français” during that period.
These conditions are cumulative, which means that if even one of them is not satisfied, désuétude cannot be raised against you, and this is often where a well-prepared file makes all the difference.
What counts as “possession d’état de Français”?
In simple terms, it means that you lived as a French citizen and that the French State treated you as one. It is not enough to feel French or to have grown up with French traditions at home, because the courts look for concrete signs that the French authorities recognised you as a national. The most common examples are a French passport or national identity card (even an expired one), registration with a French consulate, voting in French elections, a certificat de nationalité française, the recording of a foreign birth in the French civil registers, and French military service.
Two further points are worth stressing. Under article 30-3, the question of possession d’état is asked about you and about the parent through whom you claim, so a grandparent’s passport or an uncle’s identity card will not, on its own, establish that you or your parent were treated as French. The documents must also date from within the fifty-year period, since anything obtained afterwards arrives too late to help. A grandparent is not irrelevant to the analysis, however, because where a grandparent actually lived in France, that residence can prevent the fifty-year period from being completed at all, as the next section explains.
Can living in France stop the 50-year clock?
It can, provided it amounts to genuine residence rather than a visit. In 2023 the Cour de cassation, which is France’s highest civil court, held that a grandparent who had lived in France for several years meant that the family had not remained settled abroad for the full fifty years, so the claimant was entitled to prove their French nationality by descent (Civ. 1re, 17 May 2023, n° 21-50.068). The courts draw the line at temporary stays, however, and in January 2026 the same court decided that a parent’s period of study at a French university was not enough to break the chain (Civ. 1re, 21 January 2026, n° 24-16.717).
Why lost French citizenship is so hard to recover in court
Until June 2019, applicants to whom the rule applied still had a way to overcome it. The courts treated désuétude as a procedural obstacle that could be cured before judgment, so a person who obtained a French passport or registered with a consulate while the case was pending could escape it altogether.
The position changed fundamentally on 13 June 2019, when the Cour de cassation held that article 30-3 creates an irrebuttable presumption that French nationality has been lost (Civ. 1re, n° 18-16.838). Put simply, once the three conditions are met, the law concludes that French citizenship has been lost, and the court will not hear any evidence of French descent to the contrary. Steps taken after the fifty years have run out, or during the proceedings themselves, therefore come too late.
The Court has confirmed this approach on several occasions since, including in 2021 and twice in 2023, and in April 2025 the Conseil constitutionnel ruled that the rule, as the courts now apply it, is consistent with the French Constitution.
While the conclusion itself cannot be challenged, the facts on which it rests certainly can, and in practice most of these cases turn on dates: when the family settled abroad, when a parent last held a French passport, or whether someone in the family lived in France for a meaningful period.
Recent court decisions on désuétude (2024–2026)
In a decision of 27 November 2024 (n° 23-19.405), the Cour de cassation held that désuétude cannot be raised against children who were minors when the case was brought if it had not first been raised against their parent.
Two decisions from 2026 illustrate how much depends on timing. On 21 January 2026 (n° 24-16.717), the Court ruled against a claimant whose mother had been declared French by a court in 2013, because that judgment was handed down after the fifty years had already expired and so came too late to help her. On 25 March 2026 (n° 24-17.442), the Court reached the opposite conclusion in the case of a man whose mother had been declared French by a judgment of the Paris Court of Appeal in 2009, before the fifty years ran out. The lower court had ruled against him on the ground that his mother’s possession d’état of French nationality was not sufficiently established, and the Cour de cassation overturned that decision: as reported, the judgment recognising her as French before the deadline was sufficient, without further proof that she had lived as a French citizen.
Does the 50-year rule apply to Americans with French parents or grandparents?
It does. There is a widespread belief that désuétude only concerns people from former French territories, and it is true that a large share of the reported cases involve Algeria, simply because of the number of families concerned. The rule itself, however, applies to anyone who claims French citizenship through their parents and whose family has lived abroad, whatever the country and whatever the reason for leaving. Recent decisions have concerned claimants from India and Egypt, and an American, Canadian or Argentine descendant of a French emigrant is assessed under exactly the same test.
Where your French parent was born and grew up in France, the fifty-year period will generally only begin when that parent settled abroad. This means that if your father or mother moved to the United States less than fifty years ago, désuétude should not be capable of applying to your family, and your claim to French citizenship by descent will normally rest on the ordinary rules of nationality by filiation.
Certificate of French nationality (CNF) or court judgment?
A certificat de nationalité française (CNF), the certificate of French nationality, is an administrative document issued by a court clerk rather than a decision of a judge. It creates only a rebuttable presumption of nationality (a présomption simple), valid until the contrary is proved (article 31-2 of the Civil Code), in contrast to the irrebuttable presumption of loss that désuétude creates: it shifts the burden of proof onto anyone who disputes your nationality (article 30), but it does not bind the courts, and the public prosecutor can still challenge it. A CNF also benefits only the person who holds it: children and grandchildren cannot rely on a parent’s certificate as proof of that parent’s nationality in order to establish their own, although a certificate issued to a parent during the fifty-year period can count as evidence that the parent had possession d’état de Français. A court judgment declaring a person French carries greater weight, and the March 2026 decision that protected the child concerned precisely such a judgment. The French government has also indicated that, in consular procedures concerning minor children, a parent who holds only a certificate, particularly one obtained after the fifty years had expired, may not protect those children in the same way. Whatever the document, the key point remains that it must predate the end of the fifty-year period.
Did your parent lose French citizenship by naturalising abroad?
Even where désuétude does not apply, there is a second question that must always be checked, namely whether your French parent was still French on the day you were born. Under the law as it stands today, a French citizen who becomes a US citizen, or acquires any other nationality, keeps French nationality unless they make a formal declaration giving it up, so dual citizenship is permitted, and this has been the position since the law of 9 January 1973. The earlier rules were quite different, and they depended on the date of naturalisation, on the person’s sex and age, and on whether they were an adult or a minor at the time, although two rulings of the Conseil constitutionnel, in 2014 and 2025, have since allowed women to challenge losses that resulted from the difference in treatment between men and women:
| When your parent naturalised abroad | If your parent was an adult at the time | If your parent was a minor at the time |
|---|---|---|
| After 11 January 1973 | Kept, unless they signed a declaration giving it up | Kept. A minor cannot make that declaration, so French nationality could only be lost through a formal request authorised by the French government |
| 1 June 1951 to 11 January 1973 | Men kept it unless the French government authorised the loss, an authorisation granted as of right to men who naturalised after the age of 50 but which still had to be requested. Women lost it automatically, although a 2014 ruling of the Conseil constitutionnel (decision 2013-360 QPC) now allows them and their descendants to challenge that loss | Kept, because the automatic loss rule applied only to adults, unless the government authorised a loss on request |
| 20 October 1945 to 31 May 1951 | Men under 50 kept it unless the French government authorised the loss. Men aged 50 or over, and women, lost it automatically, although a 2025 ruling of the Conseil constitutionnel (decision 2025-1135 QPC) now allows these women to challenge that loss | Kept, because the automatic loss rule applied only to adults, unless the government authorised a loss on request |
| Before 20 October 1945 | Earlier legislation applies, and each case needs to be examined individually | Earlier legislation applies, and each case needs to be examined individually |
When reading this table, bear in mind that the age of majority in France was 21 until 1974, so a parent who naturalised at 19 or 20 before then was still a minor for these purposes.
If your parent became a US citizen, or a citizen of any other country, before you were born, this question should be looked at first, because a parent who had already ceased to be French had no French nationality to pass on to you.
How to reclaim French citizenship after désuétude: the article 21-14 declaration
Lost French citizenship is not always lost for good. Article 21-14 of the Civil Code allows a person who has lost French nationality through désuétude to reclaim it by making a declaration, which is usually lodged at a French consulate. To succeed, the person must show either that they have kept or built manifest ties with France of a cultural, professional, economic or family nature, or that they served in a unit of the French army or fought in the French or allied armies in wartime. The surviving spouse of someone who served in this way may also make the declaration.
Each application is assessed on its own facts
There is no checklist that guarantees a successful outcome. The officials who examine the declaration, and the courts if a refusal is challenged, look at the applicant’s situation as a whole and ask whether the ties described reflect a real and lasting attachment to France. Guidance issued by the Ministry of Justice gives examples of ties that can be taken into account, such as belonging to an association that promotes French culture, sending one’s children to French schools (for example a lycée français abroad), working for a French company or one closely linked to French organisations, owning property in France, maintaining close relationships with family members living in France, and of course living in France oneself.
The same guidance makes clear that a single element will rarely be sufficient on its own, that ties created shortly before the application are likely to be viewed as opportunistic, and that relationships with French people living abroad are not the same thing as ties with France. To give a sense of how this works in practice, a person who studied in France for several years, works for a French company and owns an apartment in Lyon is in a strong position, whereas a person whose only connection is French ancestry and a recent holiday is unlikely to succeed.
Practical points on the declaration procedure
Under article 26-1 of the Civil Code, who registers a nationality declaration depends on where it is made. A declaration made abroad is registered by the Minister of Justice (“le ministre de la justice, pour les déclarations souscrites à l’étranger”), whereas a declaration made in France, including an article 21-14 declaration, is registered by the court clerk’s office (the directeur des services de greffe judiciaires of the tribunal judiciaire). The exceptions are declarations based on marriage to a French national (article 21-2), on being the ascendant of a French national (article 21-13-1) or on being the sibling of a French national (article 21-13-2), which are received by the administrative authority in charge of naturalisations, today the Ministry of the Interior, and in France are lodged at the préfecture.
For an article 21-14 declaration, any refusal to register must be made within six months of the date on which the declarant is given a receipt (récépissé) confirming that the file is complete (article 26-3). A refusal must give reasons, and it can be challenged before the tribunal judiciaire within six months of being notified. If no refusal is made in time, the declarant is given a copy of the declaration bearing the note of its registration (article 26-4).
Two caveats are worth bearing in mind. The six months only start once the receipt has been issued. Even after registration, the public prosecutor may still challenge it within two years if the legal conditions were not met, or within two years of discovering any lie or fraud.
Nationality obtained by declaration takes effect, once registered, from the date on which the declaration was signed before the authority (article 26-5), rather than from birth, although minor children who live with the applicant can benefit from it at the same time.
The formal proof of nationality is the declaration itself, bearing the note of its registration, which is usually handed over by the préfecture, consulate or court where it was signed. If that document never arrives, the declarant should ask for it in writing, giving their full name, date of birth, the date on which they signed and any file number, and referring to article 26-4. A France services counter can help with these steps, and persistent delays can be raised with the Défenseur des droits.
How to prove French citizenship by descent: next steps
If you believe you may be French through a parent or grandparent, the first step is to establish a small number of key dates, because they will usually determine which rules apply to you:
- When did your French ancestor settle outside France?
- Did anyone in the line later return to live in France for a significant period?
- Did your French parent acquire another nationality and, if so, when?
- When were you born?
The next step is to gather whatever evidence exists that you or your French parent were treated as French by the French authorities, paying particular attention to anything dated before the fifty-year mark. Useful documents include French passports or identity cards (expired ones are still relevant), consular registration records or consular cards, French voter cards, any certificat de nationalité française or court judgment recognising your parent as French, and the French transcription of your own foreign birth certificate.
The usual starting point is an application for a certificat de nationalité française. If that application is refused, I would recommend thinking carefully before going to court, since a judgment recording the loss of nationality is noted in the margin of your birth record and is very difficult to undo. Where désuétude clearly applies, a declaration under article 21-14 may well be the more sensible route to reclaiming French citizenship.
Every family history is different, and the outcome frequently turns on a single date or a single document that is easy to overlook. If you think the 50-year rule may affect your claim to French citizenship by descent, you can contact me at contact@johnsonvigouroux-avocat.fr to arrange a review of your file.
Frequently asked questions
Can I lose French citizenship without knowing it?
Yes. Under the désuétude rule, if your family has lived abroad for more than fifty years and neither you nor your French parent was treated as French by the French authorities during that time, the courts will treat French nationality as lost, even if nobody was ever told.
Does French citizenship by descent have a generation limit?
There is no fixed limit on the number of generations. In practice, however, the 50-year rule acts as a limit, because a family that has lived abroad for more than fifty years without any sign of French citizenship can no longer prove nationality by descent.
Can I get French citizenship through my grandparents?
Often, yes, provided French nationality passed from your grandparent to your parent and then to you. The difficulty is that the longer the family has lived abroad, the more likely it is that désuétude applies, so the dates and documents in your family history are decisive.
Can I reclaim lost French citizenship?
If French nationality was lost through désuétude, you may be able to reclaim it by declaration under article 21-14 of the Civil Code, by showing manifest cultural, professional, economic or family ties with France, or service in the French armed forces. Each application is assessed on its own facts.
Sources and further reading
Articles of the French Civil Code referred to in this article (all available on Légifrance):
- Article 18: French nationality by descent (a child with at least one French parent is French)
- Article 21-14: reclaiming French nationality by declaration after désuétude
- Article 23: naturalisation abroad today, loss only by express declaration
- Article 23-6: judicial finding of loss of nationality through désuétude
- Article 26: who receives nationality declarations
- Article 26-1: who registers nationality declarations
- Article 26-3: time limits for refusing registration and challenging a refusal
- Article 26-4: registration when no refusal is made in time, and challenges by the public prosecutor
- Article 26-5: date on which a registered declaration takes effect
- Article 28: notes on the birth record concerning nationality
- Article 30: burden of proof in nationality matters
- Article 30-3: the 50-year rule (désuétude)
- Article 31-2: legal value of the certificat de nationalité française
Court decisions and other texts:
- Cour de cassation, 21 January 2026, n° 24-16.717
- Conseil constitutionnel, decisions 2025-1130 to 2025-1133 QPC of 11 April 2025, official commentary
- Conseil constitutionnel, decision 2013-360 QPC of 9 January 2014
- Conseil constitutionnel, decision 2025-1135 QPC of 25 April 2025
- Article 9 of the ordonnance of 19 October 1945 (Légifrance)
- Ministry of Justice circular of 11 June 2010 on nationality declarations
This article is for general information only and is not legal advice. It reflects French law and case law as of 5 October 2026.