For a foreign national who has settled permanently in France, naturalisation can represent the culmination of a long process of integration. It is not simply an administrative formality: naturalisation by decree is a discretionary decision of the French State, which assesses whether the applicant should be granted French nationality. Many otherwise strong applications are deferred or refused because the practical requirements have not been anticipated, whether in relation to French-language proficiency, stable resources or the lawfulness of the applicant’s residence history. These requirements were tightened significantly in 2025, particularly as regards language. This article explains the statutory conditions, the procedure before the prefectures and the French nationality authorities, the applicable time limits and the remedies available following an adverse decision.
Naturalisation by decree and acquisition by declaration: two distinct routes
French nationality can be acquired in several ways. Two mechanisms that are often confused in everyday language should be distinguished from the outset.
Naturalisation in the strict sense means acquiring French nationality by a decision of the public authorities under Articles 21-15 to 21-25-1 of the French Civil Code. It takes the form of a decree signed by the competent authorities and published in the Journal officiel. It is a discretionary grant by the State: even where an applicant satisfies the statutory requirements, the administration retains a power of assessment and may refuse the application.
Acquisition by declaration follows a different logic. The applicant relies on a right linked to a particular personal situation, and the administration principally verifies whether the statutory conditions are satisfied rather than exercising the same broad discretion. Acquisition by declaration following marriage to a French national under Article 21-2 of the Civil Code is the most common example. It requires the relevant period of marriage, continuous emotional and material community of life, and sufficient knowledge of French. Other declaration procedures exist, including for certain siblings of French nationals and some older ascendants of French nationals.
The rest of this article focuses on naturalisation by decree, which accounts for a large proportion of applications and presents the greatest practical difficulties.
Substantive conditions for naturalisation by decree
The five-year residence period and possible reductions
Article 21-17 of the Civil Code establishes the general rule:
Subject to the exceptions provided for in Articles 21-18, 21-19 and 21-20, naturalisation may be granted only to a foreign national who can demonstrate habitual residence in France during the five years preceding the application.
This five-year qualifying period requires stable and effective residence in France, with the centre of the applicant’s family ties and material interests located there. A person who works abroad and whose family lives abroad may have difficulty establishing habitual residence in France even if they hold a French residence permit.
The qualifying period may be reduced to two years in the situations set out in Article 21-18. This can include a foreign national who has successfully completed two years of higher education leading to a qualification awarded by a French institution, or a person who has rendered or is capable of rendering important services to France through their abilities and talents.
Certain circumstances may remove the qualifying residence period entirely under Articles 21-19 and 21-20. These include, in particular circumstances, people who have actually served in the French armed forces, certain nationals of countries where French is an official language, and people who have rendered exceptional services to France.
Residence in France and lawful immigration status
The residence requirement concerns more than the passage of time. The administration checks that the applicant resides in France when the naturalisation decree is made and that their presence has been lawful. A person who has been unlawfully resident during the period examined, or whose residence depended on fraudulent or otherwise problematic documentation, may face a finding that the application is inadmissible.
Article 21-27 of the Civil Code excludes certain categories from acquiring French nationality. In particular, French nationality cannot be acquired by:
- a person who is not lawfully resident under French immigration law;
- a person convicted of an offence against the fundamental interests of the Nation or of an act of terrorism;
- a person sentenced to an unsuspended term of imprisonment of six months or more;
- a person who is subject to an expulsion order that has not been repealed or a ban from French territory that has not been fully executed.
These statutory bars are mandatory and the administration cannot simply disregard them. Anyone with a previous Obligation to Leave French Territory (OQTF) should clarify the legal position before applying because an unresolved removal measure or a history of irregular residence may weigh heavily in the assessment.
Assimilation: language, civic knowledge and adherence to republican values
Article 21-24 of the Civil Code makes assimilation into the French community a condition of naturalisation:
No person may be naturalised unless they can demonstrate assimilation into the French community, including sufficient knowledge, having regard to their circumstances, of the French language, French history, culture and society, the level and assessment methods being determined by decree, together with knowledge of the rights and duties conferred by French nationality and adherence to the essential principles and values of the Republic.
The language requirement: from B1 to B2
The language requirement is one of the most concrete conditions and has also undergone significant recent change. Decree No. 2019-1507 of 30 December 2019 had set the required level at B1 under the Common European Framework of Reference for Languages (CEFR). B1 involved an ability to understand the main points of clear language and to communicate orally and in writing about familiar matters.
The threshold has since been raised to B2. Implementing measures adopted in 2025 increased the required level for applications submitted from 1 January 2026. B2 corresponds to a higher level of independent language use, including the ability to understand the essential content of concrete or abstract subjects and to communicate clearly and in detail. This reform follows the approach set out in the Minister of the Interior’s circular of 2 May 2025 on access to French nationality, which called for stricter assessment both of language ability and applicants’ financial autonomy. The circular encourages prefectures to apply the criteria more consistently and rigorously, particularly during the assimilation interview.
The applicant must prove the required level using an accepted form of evidence, such as:
- a qualification awarded by a French authority demonstrating a level at least equivalent to the statutory requirement, for example a qualification obtained after studies undertaken in French;
- a French-as-a-foreign-language qualification such as the DELF B2 or a DALF diploma;
- a certificate issued following an approved language test, including the TCF (Test de connaissance du français) in its “integration, residence and nationality” version (TCF-IRN) or the TEF (Test d’évaluation de français) in the relevant IRN version.
Approved tests assess the range of skills required at the relevant level, including written comprehension and expression as well as oral ability. Applicants should check that the certificate demonstrates the required level in each component and comes from an approved body. Certain exemptions may apply, including in specific circumstances relating to age or a duly established disability, subject to the required supporting evidence.
Civic knowledge and adherence to republican values
Knowledge of French history, culture and society is assessed during the assimilation process by reference to the themes contained in the official citizenship materials. Applicants may be asked about major events in French history, the organisation of public institutions and the symbols of the Republic.
Under the current regime, applicants must also satisfy the applicable civic-knowledge requirements, including the civic test where required.
Adherence to the essential principles and values of the Republic is a separate requirement. Secularism, equality between women and men and freedom of conscience are among the issues examined closely by the administration. Conduct regarded as incompatible with these principles may support refusal where it demonstrates a lack of assimilation. The applicant also signs the Charter of the Rights and Duties of the French Citizen.
Good character, professional integration and financial autonomy
Beyond the absolute statutory bars in Article 21-27, the administration assesses the applicant’s conduct more broadly, traditionally referred to as the requirement of “good life and character”. The investigation covers criminal history but may also consider tax and social-security compliance. Unresolved tax debts, benefit fraud or failure to declare income can lead to deferral or refusal even in the absence of a criminal conviction.
Professional integration and financial autonomy play an increasingly significant role, and the circular of 2 May 2025 places particular emphasis on these issues. The administration looks for stable and sufficient resources derived from professional activity, allowing the applicant to support themselves without long-term dependence on minimum-income benefits. An open-ended employment contract (CDI), a sustainable self-employed activity or a coherent professional history will strengthen the application. Conversely, prolonged financial insecurity or sustained dependence on minimum-income support is a frequent ground for deferral, with the administration effectively inviting the applicant to reapply once their circumstances have become more stable.
An important distinction should be understood: a deferral (ajournement) is not the same as a refusal. A deferral postpones consideration by fixing a future date, often with conditions to be satisfied, such as achieving greater employment stability or resolving tax matters. A refusal rejects the application on its merits. An inadmissibility decision, by contrast, concludes that the statutory conditions for consideration are not met. These three adverse outcomes have different consequences and may require different strategies.
The procedure: from online application to publication of the decree
Applications for naturalisation are now generally submitted electronically through the dedicated nationality platform. The file includes civil-status documents, evidence of lawful residence, resources, address and tax position, together with proof of the required French-language level. Civil-status documentation is particularly important: incomplete documents, poor translations or documents lacking any required legalisation or authentication can prevent the application from progressing.
Once the file is regarded as complete, the administration records completion and the statutory processing timetable begins. The application is then examined through several stages: verification of documents, administrative enquiries into the applicant’s circumstances and conduct, and the assimilation interview.
The assimilation interview
The individual interview with an officer is a key stage. It is used to assess practical command of French, knowledge of French history and institutions, and adherence to republican values. The officer prepares a report that carries significant weight in the recommendation sent to the central authorities. Following the 2 May 2025 circular, assessment during this interview has become more rigorous, with the officer expected to consider actual command of the language rather than simply rely on a certificate. Serious preparation using the official citizenship materials and an ability to communicate confidently in French are therefore important. Difficulty answering basic questions about institutions or expressing views incompatible with core republican principles may result in an adverse assessment.
Processing periods and possible decisions
Article 21-25-1 of the Civil Code sets a statutory processing period:
The public authority’s response to an application for acquisition of French nationality by naturalisation must be given no later than eighteen months after all documents required for a complete application have been submitted and acknowledged.
The period is reduced to twelve months where the applicant can show at least ten years of habitual residence in France on the date the complete file is submitted. It may be extended once, by a reasoned decision, for a further three months.
The process may lead to different outcomes. Where the application is approved, a naturalisation decree is made and published in the Journal officiel; the applicant acquires French nationality from the effective date of the decree.
Where the outcome is adverse, the administration may notify:
– an inadmissibility decision;
– a refusal;
– or a deferral until a specified future date.
An adverse decision must state its reasons, allowing the applicant to identify the precise basis before deciding whether to challenge it or strengthen the application for the future.
Challenging an adverse naturalisation decision
Refusals, inadmissibility decisions and deferrals are subject to a specific appeal regime. A prior administrative appeal is mandatory: before going to court, the applicant must challenge the decision before the Minister responsible for naturalisations within two months of notification. This administrative appeal preserves the route to subsequent judicial proceedings.
If the administrative appeal is rejected, or the Minister fails to respond within the relevant period, the dispute may be brought before the Administrative Court of Nantes, which has specialised jurisdiction for naturalisation disputes. The intensity of judicial review depends on the issue concerned. The court fully reviews objective statutory conditions such as the length of residence, lawfulness of status and the statutory bars in Article 21-27. It is more restrained in relation to discretionary matters such as overall suitability and assimilation, where the administration retains a broad margin of assessment.
The reasons given in the adverse decision determine the appeal strategy. A refusal based on insufficient resources calls for evidence of professional and financial stability. A refusal based on language assimilation may require objective evidence of the applicant’s actual French level, such as an updated approved test certificate demonstrating B2. In some situations, particularly following a deferral, it may be more effective to consolidate the applicant’s circumstances and submit a fresh application rather than pursue immediate litigation.
Effects of naturalisation
Acquiring French nationality has substantial consequences. From the effective date of the decree, the naturalised person enjoys the rights attached to French nationality, without retrospective effect for the period before naturalisation. These include voting rights and eligibility for public office, access to public-sector roles reserved for French nationals, and French diplomatic protection.
The collective effect on minor children deserves particular attention. Under Article 22-1 of the Civil Code, a minor child whose parent acquires French nationality may become French automatically where the statutory conditions are satisfied, including being named in the decree and habitually living with that parent, or in an alternating-residence arrangement where applicable. A child omitted from the application will not necessarily benefit automatically, which is why all minor children should be properly identified from the outset.
French law allows dual nationality: naturalisation does not require the applicant to give up their nationality of origin. Some countries of origin do not, however, permit dual nationality, so applicants should check the consequences under the law of their original nationality.
Finally, in tightly defined circumstances, the French State may withdraw nationality obtained by decree where it was acquired through fraud or false statements, and deprivation of nationality is possible only in the limited situations prescribed by law. These mechanisms are exceptional and subject to strict legal controls.
Conclusion
Naturalisation is not an automatic entitlement but a sovereign decision of the French State involving both objective conditions — residence, lawful status and absence of statutory bars — and a more discretionary assessment of assimilation and integration. Recent changes, particularly the increase in the language requirement to B2 for applications submitted from 1 January 2026 and the increased emphasis on financial autonomy in the circular of 2 May 2025, confirm a lasting tightening of the practical criteria. An application is strongest when submitted at the right time: professional circumstances are stable, the immigration history is clear and lawful, and the required French level can be demonstrated through appropriate evidence such as a TCF-IRN, TEF-IRN or DELF B2 certificate.
Before applying, it is sensible to review the consistency of the applicant’s residence history, identify any past issue that could lead to inadmissibility, verify that the language evidence meets the current requirement and ensure that civil-status documents are complete, including those relating to minor children who may benefit from the collective effect. Where there is a history of irregular residence, an OQTF or unresolved tax matters, a prior assessment of eligibility can help avoid an adverse decision that may affect the prospects of a future application.
Frequently asked questions
How long must I live in France before applying for naturalisation? The general rule under Article 21-17 of the Civil Code is five years of habitual residence before the application. The period may be reduced to two years in certain situations under Article 21-18, including for some applicants who have successfully completed two years of higher education leading to a French qualification or who can render important services to France. Other statutory situations, such as certain service in the French armed forces, may remove the qualifying period altogether.
What level of French is required for naturalisation? The language level, previously set at B1 by Decree No. 2019-1507 of 30 December 2019, has been raised to B2 for applications submitted from 1 January 2026 under the current implementing framework, in line with the stricter approach reflected in the Minister of the Interior’s circular of 2 May 2025. The applicant must prove the required level through an accepted qualification, such as DELF B2 or DALF, or an approved test such as TCF-IRN or TEF-IRN. Specific exemptions may apply in certain circumstances, including duly established disability.
Which French-language tests are accepted for naturalisation? Accepted evidence includes qualifying French diplomas demonstrating the required level, French-as-a-foreign-language qualifications such as DELF B2 or DALF, and certificates from State-approved tests, notably TCF-IRN and TEF-IRN. The certificate should come from an approved provider and demonstrate the required level across the relevant components of the assessment.
Does a previous OQTF permanently prevent naturalisation? A historic OQTF that is no longer in force does not necessarily create an absolute lifetime bar, but it raises questions about the lawfulness and continuity of the applicant’s residence history, which are central to naturalisation. Article 21-27 contains specific statutory exclusions relating to certain unresolved removal situations. The applicant’s full immigration history should therefore be reviewed before filing.
What is the difference between refusal and deferral? A refusal rejects the application, whereas a deferral postpones the outcome until a specified future date, often with matters to be resolved such as employment stability or tax compliance. A deferral therefore generally contemplates a later fresh application once the position has improved. An inadmissibility decision is different again: it means that one or more statutory conditions are not satisfied.
How long does the administration have to decide the application? Article 21-25-1 of the Civil Code provides for a response within eighteen months after submission of a complete application against acknowledgement. The period is reduced to twelve months for an applicant who can show at least ten years of habitual residence in France and may be extended once by three months through a reasoned decision. Actual processing times may nevertheless be longer in practice.
How can I challenge a refusal of naturalisation? A prior administrative appeal to the Minister responsible for naturalisations is mandatory and must be made within two months of notification. If that appeal is rejected, the dispute may be brought before the Administrative Court of Nantes, which has jurisdiction over these matters. The appropriate arguments depend on the reasons given for the adverse decision.
Does naturalisation require me to give up my original nationality? French law permits dual nationality and does not require an applicant to renounce their nationality of origin. However, the law of the country of origin may take a different approach, so the applicant should check the consequences under that country’s nationality law.
