How to File a Patent in France: 6 Smart Steps

France sits at the centre of the European patent system — it is a founding member of the Unified Patent Court and hosts the UPC Central Division in Paris — yet its national procedure has quietly become one of the most demanding in Europe. If you are weighing how to file a patent in France, two things separate it from most jurisdictions: since the 2020 PACTE reforms the French office now examines inventive step and allows post-grant opposition, and a PCT application cannot enter the French national phase directly. This guide covers the routes, the fees, and the deadlines that end a case if you miss them.

How to File a Patent in France: Three Routes That Actually Differ

There are three ways into French patent protection, and the choice is strategic, not just administrative. Deciding how to file a patent in France means picking between a national right, a European right, or the international system:

1. National filing at INPI — a French patent, searched and examined by the Institut national de la propriété industrielle, covering France only.
2. European patent via the EPO — granted centrally by the European Patent Office and then taking effect in France, either as a classical validated patent or as a Unitary Patent.
3. PCT route — an international application that reaches France only through the European regional phase at the EPO; there is no direct French national phase.

For France-only protection, a direct INPI filing is cheapest. If you want several European countries, the European patent route is almost always more efficient than filing nationally in each. The PCT route sits on top, buying time before you commit — but, as we explain below, in France it always runs through the EPO.

Route 1: A National Filing at INPI

You file the application with INPI in French; if you file in another language you must supply a French translation within a set period. The big change every applicant should know: since the PACTE law took effect on 22 May 2020, INPI conducts a full substantive examination. It can now refuse an application for lack of inventive step, not only for lack of novelty or industrial application as before. France also introduced a post-grant opposition procedure on 1 April 2020, letting third parties challenge a granted French patent at INPI within nine months of grant.

France also offers a second, faster right: the utility certificate (certificat d’utilité). PACTE extended its term from six to ten years and made it convertible into a patent application. It follows the patent rules but needs no search report and is not open to opposition — useful for a shorter-lived or budget-sensitive invention. A French patent itself lasts up to 20 years from filing, with annual renewal fees due from the second year. Confirm current fees on INPI’s own patent pages before you budget.

Route 2: A European Patent That Takes Effect in France

France is a founding member of the European Patent Convention (EPC), so a European patent granted by the EPO can take effect here. There are two flavours. A classical European patent is validated in France after grant; because French is an official EPO language and France is a London Agreement country, no translation of the patent is required to validate — a genuine cost saving. Alternatively, you can request unitary effect and obtain a Unitary Patent that covers France and the other participating states with a single renewal fee.

The validation deadline is short — typically three months from the mention of grant — so it must be diarised the moment grant issues. Our European patent validation guide and our Unitary Patent and UPC guide cover the mechanics in depth.

Route 3: The PCT Route Into France

Here France is unusual, and getting it wrong is costly. A PCT application cannot enter the French national phase directly — France has closed its national route. To reach France from an international application you must enter the European regional phase at the EPO (deadline 31 months from priority); the resulting European patent then takes effect in France. There is no 30-month direct INPI national-phase filing to fall back on.

Whichever way you go, the priority chain is the same: file, claim priority within 12 months under the Paris Convention if you filed abroad first, then hit the 31-month EPO regional-phase deadline. See our Paris Convention priority claim guide and our Euro-PCT regional phase entry guide for the details.

National, European, or Unitary: Which Right Fits?

The route is not just a filing decision — it sets your cost base, your geographic reach, and how a future dispute unfolds. A national INPI patent makes sense when France is your only real market, when budget is tight, or when you want the option of a fast utility certificate alongside it. It is the leanest path, but it protects nothing outside France.

A classical European patent validated in France suits an applicant who wants France plus a handful of other EPC states and prefers to keep national courts in play, opting out of the Unified Patent Court. A Unitary Patent, by contrast, gives broad single-renewal coverage across the participating states — France included — and locks you into the UPC for enforcement and revocation. That trade — wider reach and simpler renewals versus a single court that can revoke the patent everywhere at once — is the central strategic call for anyone filing today.

In practice, many foreign applicants file a PCT application first, enter the European phase at the EPO, and decide between unitary effect and classical validation only at grant, when they know which markets have proven worth the money. Keeping that decision open is often the smartest part of the plan.

Costs and the Deadlines You Can’t Miss

A national INPI filing is inexpensive to start — the filing and search-report fees are modest — but renewal fees climb each year to encourage applicants to drop weak patents. The European route costs more up front (EPO filing, search, examination and grant fees) but can be cheaper than validating in many countries separately. Budget realistically and get current figures from the office before filing.

• INPI substantive examination: automatic since PACTE (filed from 22 May 2020).
• Opposition against a French patent: within 9 months of grant, at INPI.
• European validation in France: generally within 3 months of the grant mention.
• PCT into France: 31 months to the EPO regional phase — no direct national phase.
• Paris Convention priority: 12 months from your first filing.

Where French Patent Disputes Are Heard

France concentrates patent litigation in one place: the Paris Judicial Court (Tribunal judiciaire de Paris) has exclusive national jurisdiction over patent infringement and validity, with appeals to the Paris Court of Appeal. That single specialised forum is one reason France is a favoured venue for pan-European disputes. Since June 2023, France is also a member of the Unified Patent Court and hosts the UPC Central Division in Paris, which hears infringement and validity together for European patents that have not been opted out.

That choice of forum shapes strategy from day one. If you expect to enforce, an early patent invalidation search in Paris or a focused prior-art litigation search in Lille can sharpen your position. Our France IP services hub lays out the full local footprint.

How PerspireIP Can Help You File in France

The French system now rewards applicants who plan the route, the examination and opposition risk, and the enforcement forum together. PerspireIP helps inventors and foreign applicants choose between the INPI, EPO and PCT paths, meet every deadline, and prepare for the French courts or the UPC. Talk to our team about your French filing. This article is general information, not legal advice; consult a qualified attorney for your situation.

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