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Patent infringement actions in France

The French law provides for a strong ex parte procedure of obtaining evidence of infringement. The Court then decides on both the validity of the patent and its infringement.



Importation of patented products as well as manufacturing in France of patented products, are considered direct infringement. In the same way offering patented goods, selling, or using such goods is a direct infringement.

The same is true for working in France a patented method of manufacturing or knowingly offering third parties to work in France a patented method of manufacturing. Also infringing are the offer, selling and importation in France of a product manufactured abroad according to a manufacturing method patented in France.

Contributory infringement is further defined as delivery or offer to deliver in France to unauthorized persons means for performing or obtaining the patented invention when those are essential means and when it is obvious that those means permit to perform or to obtain the invention.

In case of staple means it is further necessary that evidence of incitement be forwarded.

The alleged infringer can be sued without prior notice if the infringement acts are the importation in France of patented products, the manufacturing in France, the working in France of a patented method or the importation of products manufactured abroad according to a patented method.

On the contrary, it is necessary to send first a warning letter to potential infringers which are only selling, using or otherwise handling infringed products, or forwarding means permitting to manufacture infringed goods.


The infringement action may be engaged on the basis of a pending French patent application. If the application has not yet been laid open to public inspection, a certified copy of the patent application must first be served together with a warning letter to the potential infringer.

The infringement begins with the receipt of the letter.

Such a warning letter is not necessary in case of a published French patent application or a granted French patent.

In the case of a European patent application designating France, the action can only be brought after publication of the application by the European Patent Office and laying open of a French translation of the claims by the French Patent Office.

In the case of a European patent designating France and granted in English or German, a French translation of the complete patent will have to be produced before the Court.


Infringement seizure is the first step generally used in France to gain evidence of the infringement. This procedure is ordered by the judge upon request of the patentee on the sole basis of an existing patent or patent application together with evidence of maintain into force and ownership of the plaintiff. This procedure is fully ex parte and is made without any notification to the alleged infringer.

The law provides that the judge may authorize the patentee upon simple request to appoint an official of the courts (a bailiff) assisted by any useful expert (in practice the patent attorney representing the patentee) to ascertain evidence of infringement.

In practice, during the infringement seizure which can be made in the factory of the alleged infringer, it is possible for the bailiff in execution of the order of the judge, to make a description of an alleged infringement (product or method) and to seize samples of any alleged infringing product. The bailiff is normally assisted by the patent attorney of the patentee, together with a police representative and any useful assistant (such as a photographer...).

The bailiff, together with the patent attorney, establishes a report together with any useful enclosures (photographies, photocopies, notices about the infringed goods or method...). This report which is left to the party at which the seizure was made, will be the basis for the subsequent infringement action.

Evidence relating to the infringing product or process may be completed afterwards by requesting the Court to order the production of all information relating to the origin of the alleged infringement, the distribution network as well as quantities and prices.


Within thirty days from the day of the infringement seizure, it is necessary to serve a writ to at least one of the alleged infringers, in order to validate the seizure. The writ is a rather short statement of the main arguments of the plaintiff, stating for example the main characteristics of the invention and the similar characteristics which have been reproduced as evidenced by the seizure report. The writ must contain the exact and preferably complete list of claims allegedly infringed in view of the infringement seizure. The writ also contains at its end a summary of requests made by the plaintiff concerning final injunction, order for determination of damages and other remedies. The writ is served to all the alleged infringers.


According to the French procedural Code, the action is brought before the Paris District Court which, since November 2009, is the only French Court having jurisdiction in patent matters.


Upon providing sufficient evidence of infringement, the patentee may request interlocutory injunction to the President of the first instance court even before engaging the action on the merit.

The patentee has to show the likelyhood of the infringement.

The decision may be rendered by the President of the court upon request for interlocutory injunction after a few months, and may be appealed to the court of appeal.


After the writ has been served, the defendant has a delay for filing a brief mentioning his main argumentation. In defence, the defendant may argue non infringement, as well as challenge in a counter claim the validity of the patent in suit. Both issues are considered in the same instance and by the same court.

The brief is a rather short document in which the defendant may argue that he is not infringing the patent and/or that the patent is not valid due to the state of the art or a lack of disclosure or any other reason stated in the law.

The final deadline for filing such a first brief for the defendant is usually six to twelve months after receipt of the writ.

The plaintiff may then file a brief in response, showing for example that the invention remains patentable even with the state of the art mentioned in the brief of the defendant.

Further exchanges of briefs may occur between the parties. While it is possible to introduce new argumentation and new references in a further brief, it is of course preferable to maintain the same line of argumentation from the beginning.


Usually the French courts do not deem necessary to appoint a technical expert. However, in certain instances, the parties will prefer to request the court to nominate a technical expert. This will be particularly necessary when the patent in suit concerns a chemical product which needs some analyses or technical comparison testing.

If the court decides to nominate a technical expert, the court will normally set a certain number of questions to the expert. The expert will then convey the parties at several meetings at which the parties will expose their argument and try to convince the expert of their position. Depending upon the length and difficulty of testing which the expert has to make, the duration of the expertise may well extend to one or two years.

At the end, the expert will issue a report giving the answers to the questions of the court and the parties will have the opportunity to discuss the conclusions of the expert in further briefs before the court.


After a certain number of exchanges of briefs (usually two to four exchanges) the judge decides to close the case and gives a deadline for filing further briefs as well as a date for the oral hearing. The oral hearing usually takes place about two years after the filing of the initial writ, except in case of nomination of an expert, which increases the duration of the procedure for approximately one supplemental year.

The oral hearing must be very thoroughly prepared with the barrister. The pleadings of the barristers are based on the argumentation developed in the briefs. However, it happens frequently that the barristers go slightly beyond the short argumentation of the briefs. It is therefore necessary to be prepared to possible slight deviations from the argumentation explained in the briefs of the other party.

The pleadings of each barrister last about one to three hours, the plaintiff speaking first and the defendant in second with a further possibility of answer of the plaintiff’s barrister at the end.

Usually, the oral hearing lasts one full afternoon and sometimes in difficult cases two afternoons.

After the pleadings both barristers give to the court (three judges) their dockets which contain by writing the main arguments they have developed during oral pleading.

The court gives its decision within one or two to three months from the oral hearing.


If the plaintiff wins the case, the decision of the first instance will usually order immediately the nomination of an accounting expert to begin determination of damages. The decision may also order an immediate payment of a provisional amount of damages.

Depending on the case, the decision of the first instance may order injunction to cease infringement. In that case, the alleged infringer must stop selling or manufacturing the infringing products during the entire appeal proceeding if the defendant files an appeal.


Those proceedings are very similar to the proceedings of the first instance and last about the same time. The Paris Court of Appeal is the only appeal court having jurisdiction on patent matters.

Consequently, the parties exchange briefs stating their argumentation by writing. It must be noted that during appeal, the parties are not limited to arguments, grounds and evidence used in the first instance, but may use new arguments, file new evidence and base their argumentation on new references of the state of the art.

The general outline of the oral hearing, which again takes place approximately after two years of the decision of the first instance before the court of appeal (three judges), is similar to the one of the oral hearing in the first instance.

If the plaintiff wins the case, the court of appeal will at that time give a definitive order of injunction to cease the infringement.

From that decision therefore the defendant cannot any more pursue the infringement acts. The defendant may be condemned to high fines if he continues such an infringement.

The court may also decide destruction or delivery to the patentee of infringing goods or means for manufacturing infringing goods and publication of the decision.

In the meantime, if the decision of the first instance was also favourable to the plaintiff, the accounting expert will probably have finished to determine the amount of damages. If on the contrary the appeal decision reverses the first instance decision and is in favor of the plaintiff for the first time, the court will appoint an expert to determine damages.

Normally the injunction and determination of damages are limited to infringement in France.

However, cross border injunctions and decisions extending their effect outside of France may be contemplated in accordance with the provisions of the Community Regulation corresponding to the Brussel’s Convention.


Damages should correspond exactly to the prejudice suffered by the plaintiff.

The Court must take into consideration the loss of profits suffered by the patentee as well as the benefits made by the infringer.

The profit loss of the patentee is usually calculated by taking into consideration the number of infringed products sold or manufactured by the infringer and the usual margin which the patentee takes for the patented product. When the patented product is only a portion of a more important apparatus, the court will determine whether the apparatus including the patented portion can be considered or not "a whole" commercially speaking or "a whole" on the basis of the material structure. The court will therefore compute a possible modification of the damages. The court will also take into consideration the potentialities of both the infringer and the patentee in order to determine whether the patentee would have been in the position of manufacturing or selling in the same way as the infringer.

Alternatively, and upon request of the patentee, the Court may determine the damages on the basis of a normal licence fee in the technical field in question.

In practice, the amount of damages is determined by an accounting expert nominated by the court either at the end of the first instance, if the court of first instance recognizes infringement, or only at the end of the appeal procedure.

The accounting expert organizes several meetings with the parties and is authorized to check the accounts of both parties. Pertinent information must be comunicated by each party.

When the accounting expert has terminated the determination of the damages, he will file a report giving his conclusions to the court which has nominated him. If this is the court of first instance, said court of first instance will take a decision on the amount of damages on the basis of the expert report. Before that decision, however the parties may again file to the court of first instance their argumentation by exchanging briefs during a time which may last one or two years. After such an exchange, a new oral hearing takes place before the court where both barristers explain their position relating to the determination of the damages.

If the decision rendered on damages is a decision of the first instance court, it is possible for any party to appeal the decision before the court of appeal where the determination of the damages is again discussed in the same way as before the court of the first instance.

This, again, necessitates exchange of briefs and may last one or two years.

If the expert was nominated by the appeal court, the procedure is held before the appeal court which takes a final decision on damages.

The amount of the damages may be reevaluated in view of the time elapsed.


The court usually awards the winning party a fixed amount generally less than 50 000 Euros in compensation for the expenses and attorney’s fees paid by the winning party during the suit.

In the same way the defendant only rarely receives any substantial damages in the case the court finally declares the patent void or not infringed.


Any decision of a court of appeal may be submitted, on a matter of law only, to the "Cour de Cassation" (Supreme Court). However, the proceedings before this court do not modify the injunction order given by the court of appeal during the meantime. This means that the infringer may not continue infringement after a decision of the court of appeal stating infringement of a valid patent.

The "Cour de Cassation" only handles cases which it deems suitable. In all other situations, the case is simply dismissed without any decision (approximately 70% of the cases).

If the "Cour de Cassation" accepts to hanlde the case, both parties file their arguments by writing and a decision of the Court (three judges) is taken after approximately one or two years.

If the decision considers that the decision of the court of appeal was well founded, this ends the proceedings.

If, on the contrary, the "Cour de Cassation" decides that the decision of the court of appeal was not well founded by law, the decision of the court of appeal is cancelled and the whole case must be again decided by the court of appeal with another panel of judges. Before the court of appeal, the parties will again exchange their arguments by filing of briefs and an oral hearing will take place. The proceeding will be exactly similar to a normal appeal proceeding. However, in practice, the court of appeal will usually follow the indications given by the Supreme Court.

In extremely seldom cases, the court of appeal may take the same decision as the previous court of appeal and it is then possible to apply again to the Supreme Court with, this time, five judges which will take a final decision compulsorily followed by a third decision of the court of appeal.