Patent enforcement proceedings

Lawsuits and courts

What legal or administrative proceedings are available for enforcing patent rights against an infringer? Are there specialised courts in which a patent infringement lawsuit can or must be brought?

All patent litigation has been centralised within the Third Division of the Paris Judicial Court (Tribunal Judiciaire since 2020), which is devoted exclusively to intellectual property (IP) cases and has jurisdiction for both infringement or validity matters.

This division is composed of specialist judges in French and European patent law. Cases on the merits are handled by a bench of three judges, while preliminary injunctions and ex parte proceedings are brought before one judge.

Approximately one-third of the cases ruled in the first instance are submitted to the Paris Court of Appeal, in which two sections have jurisdiction to review IP judgments. The Court of Appeal rules on both fact and law issues.

The legality of the decision of the Court of Appeal can be appealed in cassation before the French Supreme Court, which will assess whether the decision has been rendered in accordance with French law. The Supreme Court will therefore rule only 'in law' (ie, by applying and construing French law) and does not re-examine the facts. 

The first instance decision in patent cases is all the more crucial since the confirmation rate before the Court of Appeal exceeds 70 per cent of the cases and is even higher before the Supreme Court. Over the past two years, however, the Court of Appeal's level of requirement when granting preliminary injunctions seems to have increased, which may have led to reversals of first instance decisions. This suggests that the position of French courts on the criteria to grant a PI is currently debated.

Trial format and timing

What is the format of a patent infringement trial?

A patent infringement trial on the merits is divided into three parts:

  • A pretrial phase: a single judge defines the schedule within which each party shall deliver its own written submissions and supporting documents. The parties rarely exchange fewer than two sets of submissions replying to each other. Since 2019, the powers of this pretrial judge have been extended, affecting patent litigation practice. Inadmissibility claims and procedural motions shall be now held by the pretrial judge, having exclusive jurisdiction in this regard.
  • A short final oral hearing: this may take one hour to half a day, depending on how technical the case is. This hearing is used to make the judges understand the key technical elements of the patent and gauge the legal reasoning of the parties in view of the supporting exhibits.
  • The deliberations: the decision is rendered between one and three months later, depending on the complexity of the case and the workload of the court.


By virtue of the adversarial principle, the hearings are solely based on the written reasoning presented in the briefs. Likewise, all pieces of evidence must have been brought to discussion before the final hearing.

There is no concept of cross-examination, all evidence being almost exclusively written.

French patent cases are exclusively decided by judges. No jury is involved.

In rare cases, the judges may decide to appoint and interview a legal expert to enlighten them on technical issues or on the assessment of damages. The expert delivers a written report that is challenged by the parties. The judges are usually guided by the opinions expressed by the expert, but they are not bound by them.

In high-profile or technical cases, it is also common practice for the parties to support their opinions with the report of their own privately appointed expert.

Proof requirements

What are the burdens of proof for establishing infringement, invalidity and unenforceability of a patent?

The burden of proof lies with the claimant for establishing the infringement of its rights. The claimant may request an authorisation to conduct an infringement seizure aiming to find more evidence on the infringement and the quantum of the damages.

The claimant shall also demonstrate its standing to sue and justify that the patent is still in force with proof of payment of the last annual fee.

The burden of proof for invalidity or unenforceability of the patent lies with the defendant.

Standing to sue

Who may sue for patent infringement? Under what conditions can an accused infringer bring a lawsuit to obtain a judicial ruling or declaration on the accusation?

The right to bring an action for patent infringement belongs to the patent owner.

Such right may also be granted to the exclusive licensee subject to the following requirements:

  • the licence agreement does not stipulate otherwise;
  • the licence agreement is in writing and registered in the patent registry; and
  • the patent holder does not initiate the proceedings despite the licensee’s official letter inviting him or her to do so.


Any licensee (either exclusive or non-exclusive) can join the proceedings to obtain compensation for its own damages.

In all but a few cases, the accused infringer replies to the claimant by bringing a counterclaim for patent invalidity. Sometimes the defendant replies by claiming ownership of the patent; for instance, in cases where claimant and defendant were former partners.

The accused infringer may also add to his or her defence a counterclaim for frivolous proceedings, which is successful in about 10 per cent of cases.

Inducement, and contributory and multiple party infringement

To what extent can someone be liable for inducing or contributing to patent infringement? Can multiple parties be jointly liable for infringement if each practises only some of the elements of a patent claim, but together they practise all the elements?

Contributory infringement of patents is prohibited under French law. Unless agreed by the patent owner, it is prohibited to supply or offer to supply, on French territory, the means of implementing an ‘essential part’ of the invention to any person other than a person entitled to work the patented invention.

Such prohibition applies where the third party knows, or where it is obvious from the circumstances, that such means are suitable and intended for putting the invention into effect.

The prohibition does not apply where the means of implementation are staple commercial items, except where the patent owner is able to demonstrate that the third party induced the person to whom it supplies to commit infringing actions.

French law does not provide for joint liability in the case where each party only practises some of the elements of the invention. Multiple parties can be held jointly liable for patent infringement only if they practise all the elements together.

Joinder of multiple defendants

Can multiple parties be joined as defendants in the same lawsuit? If so, what are the requirements? Must all of the defendants be accused of infringing all of the same patents?

In the case where multiple parties are involved in the same patent infringement, they can be joined as defendants in the same lawsuit. For instance, multiple parties involved in the various steps that lead to the same offer or putting on the market of infringing goods, such as the manufacturer, the wholesaler, the seller, etc.

Infringement by foreign activities

To what extent can activities that take place outside the jurisdiction support a charge of patent infringement?

French courts have jurisdiction over any of the following activities, as long as they are performed in France:

  • manufacturing, offering, putting on the market, using, importing or possessing for the aforesaid purposes the good covered by the patent;
  • using a process covered by the patent (provided the third party knows that such use is prohibited without the consent of the patent holder); or
  • offering, putting on the market, using, importing or possessing for the aforesaid purposes the goods directly obtained through the process covered by the patent.


As to online sales, French courts declare themselves competent where the website is targeting French consumers and has a business impact on French territory, making use of a bundle of indicators, including the language and currency used and the international activity of the merchant, etc.

The Paris Court of Appeal recently clarified the competence of French courts to rule on patent infringement acts committed abroad. It ruled that (1) French courts do not have jurisdiction to rule on infringing acts committed outside France (Germany and UK) against a European patent, either by a foreign company that is a national of an EU member state or by a non-EU defendant; (2) in contrast, French courts have jurisdiction over infringing acts committed outside French territory (Germany and UK) by a French defendant (24 November 2020, RG No. 20/04780).

Infringement by equivalents

To what extent can ‘equivalents’ of the claimed subject matter be shown to infringe?

The French Intellectual Property Code does not provide for any rule governing infringement by equivalents.

The ‘theory of equivalents’ is governed by case law, which requires that the structure of the product, although different, shall fulfil the same function, to achieve the same result or a similar one.

However, the function of the means expressed in the claim must not be previously known over prior art (for in such case the patent can only protect the means in its form, but not in its function).

Discovery of evidence

What mechanisms are available for obtaining evidence from an opponent, from third parties or from outside the country for proving infringement, damages or invalidity?

No discovery procedure exists in France; the parties are free to disclose evidence they choose, provided it is not privileged.

The infringement seizure (saisie-contrefaçon) is one of the most common probative tools used by French practitioners. As a consequence, many cases may either succeed or fail depending on whether the seizure was well or badly performed.

Such measure is obtained through an ex parte procedure by anyone who has the quality to bring an infringement action, leading to a detailed authorisation granted by a single judge. The purpose is to create surprise and avoid dissimulation of proof by the alleged infringer. Only a bailiff can perform the seizure, generally accompanied by an expert or patent attorney designated by the patentee, and by police officers if need be, to the exclusion of any person related to the claimant (employees or officers) or its counsel.

As its goal is to provide evidence for the infringement and the quantum of the prejudice, the bailiff may seize samples of infringing goods and any technical information or any financial, accounting or commercial documents needed for the assessment of the prejudice suffered by the patentee.

The claimant shall bring proceedings leading to a decision on the merits within 20 working days or 30 calendar days, failing which the search and seizure shall be held invalid.

Following the transposition into French law on 30 July 2018 of the EU Directive 2016/943 on trade secrets, documents seized tend to be more and more frequently placed under escrow. Documents are disclosed within 30 days of the performance of the seizure, subject to opposition by the seized party. In the case of an opposition within this time frame, an expert is usually appointed by the Court to sort out which information falls within the field of the infringement seizure as authorised by the Court and which do not. Information that is within this scope shall be disclosed to the seizing party even though it is secret.

Litigation timetable

What is the typical timetable for a patent infringement lawsuit in the trial and appellate courts?

From the delivery of the writ of summons to the decision, the proceedings last on average 18 to 24 months in the first instance and about the same at appeal.

Litigation costs

What is the typical range of costs of a patent infringement lawsuit before trial, during trial and for an appeal? Are contingency fees permitted?

The costs for patent litigation vary hugely depending on the technical complexity of the case. To obtain a first decision, the range varies between €30,000 and €150,000.

Very complicated and technical cases, such as pharmaceutical litigation, may exceed €250,000.

Such range does not include the costs generated by a search and seizure measure, the seeking of a preliminary injunction, the appointment of a legal or private expert, etc.

Appeal costs may be slightly lower.

Over the past few years, the compensation for legal costs awarded to the winning party has tended to increase.

Pure contingency fee agreements (pacte de quota litis) are prohibited under French law. Contingency fees can only come as a complement to usual fees (flat fees or hourly rates) and agreed in writing by the client.

Court appeals

What avenues of appeal are available following an adverse decision in a patent infringement lawsuit? Is new evidence allowed at the appellate stage?

A recourse lodged before the Paris Court of Appeal is the only avenue of appeal available against a decision in relation to patent infringement.

The parties can produce new evidence at the appellate stage only if it is aimed at supporting the claims submitted at first instance.

Competition considerations

To what extent can enforcement of a patent expose the patent owner to liability for a competition violation, unfair competition, or a business-related tort?

French case law offers examples where the publication of warning letters against the alleged infringer before obtaining a final decision, the mere disclosure of a pending suit to the public, or the publication of a definitive court decision in a misleading manner were qualified as unfair competition.

Enforcing a patent may also be a means of distortion of competition in the relevant market according to antitrust laws.

Alternative dispute resolution

To what extent are alternative dispute resolution techniques available to resolve patent disputes?

Various forms of alternative dispute resolution (ADR) are available under French law. Arbitration, mediation and conciliation are available even though they are seldom used.

However, it is prohibited under French law to submit to arbitration matters that are governed by public order.

Therefore, as concerns patent litigation, contractual disputes (mainly about assignments, licences and manufacturing agreements) and issues related to ownership of a patent are within the scope of arbitration, whereas criminal liability for infringement and invalidity proceedings can never be resolved by ADR.

The arbitrability of civil liability for infringement has never been admitted by French judges so far, but legal doctrine tends to agree with it.

Law stated date

Correct on

Give the date on which the information above is accurate.

March 2021.