How to file a French patent application (INPI)

Filing formalities

Patent applications are filed exclusively online, on the patents portal of INPI's e-procédures service (INPI). Since 19 November 2018 the technical content, meaning title, description, claims, abstract and any drawings, has to be a single Open XML (.docx) file in the format INPI specifies. The only exception is an invention that may concern national defence, which must be filed on paper.

To get a filing date you need details that identify the applicant and let INPI contact you, and either a description or a reference to an earlier application (number, date and office). If something is missing, INPI gives you one month to complete the file, and the filing date becomes the day the last element arrives (INPI). For the application to be regular you then need at least one claim, an abstract, the filing and search fees (payable up to one month after filing) and the designation of the inventors, which can wait until 16 months from filing.

Defence review. Every application goes to the Ministry of the Armed Forces, which has up to five months to decide whether to impose secrecy. Until you have authorisation, you may neither disclose nor exploit the invention. In practice the authorisation usually comes within four to six weeks of filing. For a "sensitive" invention, French law requires a first filing at INPI before any filing abroad.

Filing in English: the French translation rule

The application documents can be filed in a foreign language, as long as a French translation is filed within two months of receiving INPI's invitation to provide it (INPI). If you file by reference to an earlier application instead of a description, you have two months to supply a copy of that application and its translation (INPI).

The practical consequence: an English draft prepared for the EPO or the USPTO can be filed at INPI the same day to secure a French filing date and priority, with the translation done once INPI asks for it. Budget for the translation, because it becomes the text INPI examines. The deadline is short, so have the translator lined up before you file.

The search report and written opinion

INPI's examination has an administrative part (form, fees, documents) and a technical part (technical character, unity of invention, consistency between description and claims). The centre of it is the preliminary search report (rapport de recherche préliminaire, RRP). It lists the most relevant prior art found worldwide, and it always comes with a written opinion on novelty and inventive step against those documents (INPI). INPI's guide places the report before the end of the 12-month priority year (Le guide du brevet), which makes a French first filing a cheap way to get an examiner's view before deciding on a European or PCT filing.

• Your reply. If relevant prior art is cited, you must reply within 3 months, extendable once on request, with observations, amended claims, or both. Amendments must stay within the description as filed. If a reply is required and you do not send one, the application may be refused.
• Publication. The application is published in the Bulletin officiel de la propriété industrielle (BOPI) 18 months from the filing or priority date, with the search report if it is ready. You can ask for early publication, under conditions.
• Third-party observations. For 3 months after the search report is published, anyone can send INPI observations citing further prior art. You get 3 months, extendable once, to answer.
• Final search report and grant. When INPI considers the application patentable it issues the final search report and invites you to pay the grant fee within 2 months. The median time to grant is about 30 months.

Inventive step is now examined. For applications filed from 22 May 2020, the PACTE law lets INPI refuse an application that lacks inventive step (art. L. 612-12 of the Intellectual Property Code). Applications filed earlier are still examined under the old rules. The assessment follows the search report and written opinion and takes your reply into account (INPI, 20 May 2020).

INPI fees

These are the amounts in INPI's schedule of procedural fees applicable from 2 July 2026. The reduced rate is half the full rate and is open to individuals, non-profit teaching and research bodies, and companies with fewer than 250 employees of which no more than 25% is held by an entity that does not meet the same condition. You claim it at filing (INPI tariffs).

Late payment of the filing or search fee costs a 50% surcharge. Example: an application with 15 claims costs €846 in official fees to grant (€26 + €520 + 5 × €42 + €90), or €423 at the reduced rate. A regular utility certificate application pays only the filing fee, since there is no search report.

Annuities

The first annuity is included in the filing fee. From the 2nd year you pay one every year, for the application as well as the patent, by the last day of the month of the filing anniversary. Payment is accepted up to one year early. Within six months after the due date you can still pay with a 50% surcharge; after that the right lapses, subject to restoration (INPI).

At the full rate, annuities for years 2 to 20 total €5,910. A utility certificate pays the same scale up to year 10: €860.

Timeline to grant

INPI's own guide gives these times as indications only. You can accelerate examination free of charge under the Patent Prosecution Highway if a partner office has found the same or narrower claims patentable (INPI). A patent lasts up to 20 years from filing, provided the annuities are paid.

Opposition at INPI since April 2020

Before the PACTE law, a granted French patent could only be challenged in court. Since 1 April 2020 anyone except the owner can oppose a French patent at INPI, without having to show an interest (INPI, s'opposer à un brevet).

• Deadline: nine months from publication of the grant mention in the BOPI. There is no restoration if you miss it.
• Grounds: the subject matter is not patentable (arts. L. 611-10, L. 611-11 and L. 611-13 to L. 611-19 CPI), the invention is not disclosed clearly and completely enough, or the patent goes beyond the application as filed.
• Scope: French patents only. Utility certificates, SPCs and the French part of a European patent cannot be opposed at INPI.
• Fee: €600, filed online with a written statement of grounds and evidence.
• Procedure: admissibility, then a written exchange with an optional public oral hearing, then a decision by INPI's director general to revoke, maintain as amended or maintain as granted. If no decision is made within 4 months of the end of the written phase, the opposition is deemed rejected. Appeals go to the Paris Court of Appeal.

The utility certificate (certificat d'utilité)

A utility certificate protects an invention on the same patentability criteria as a patent: novelty, inventive step and industrial application. The differences are procedural (INPI):

• 10 years, not 6. The PACTE law extended the maximum term from 6 to 10 years (INPI, 27 May 2019).
• No search report. INPI does not search the prior art, so the certificate is faster and cheaper to get. A search report is required if you bring an infringement action.
• Conversion. Since 11 January 2020, a utility certificate application can be turned into a patent application until the technical preparations for publication, about 16 months from filing, by paying the search fee. A patent application could always be turned into a utility certificate.

It suits products with a short commercial life, or applicants who want a granted right quickly and a search only if a dispute arises. Germany has a comparable right, the Gebrauchsmuster, with a 10-year term and a grace period that France does not offer.

The provisional application (demande provisoire)

Since 1 July 2020 you can file a provisional patent application for €26 (€13 reduced), with just a description, in any language (INPI). Claims and abstract are optional. Within 12 months you either convert it into a regular patent application, paying the €520 search fee, or into a utility certificate. You cannot add technical matter at conversion, so the description has to be complete from the start. If you do nothing, it is deemed withdrawn and never published. It also gives a 12-month priority right for filings abroad.

French patent, European patent or Unitary Patent

A French patent covers France only. For several countries, a European patent application gives one examination and one grant, and France is one of the 18 EU states covered by a Unitary Patent. If you validate a European patent nationally in France instead, no French translation is required, because France ratified the London Agreement, in force since 1 May 2008. Residents of France can file European applications through INPI.

The common pattern is a first filing at INPI, often in English with a translation to follow, then a European or PCT application within 12 months that claims its priority, using INPI's search report and opinion to decide whether the foreign filings are worth paying for. Note that France offers a 10% reduced corporate tax rate on income from licensing or selling patents; see the comparison in the UK Patent Box guide.

More INPI guides

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• Patentability search: how to check novelty before you file

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• Freedom-to-operate search in the US and Europe

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• The PCT application: timeline, fees and national phase

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• How much does a patent cost?

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• How long does a patent last?

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• Can AI write a patent application?

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