Limitation period for infringement actions

The limitation period for infringement actions confines the patent holder's right to sue to five years. Article L. 615-8 of the Intellectual Property Code runs this period from the day the patent holder knew or ought to have known of the last fact enabling it to bring the action. This rolling starting point aligns patent law with the general rule of Article 2224 of the Civil Code, which adopts the same duration and the same wording.

Calculating the limitation period

Infringement is renewed with each act of exploitation. Each infringing act therefore starts its own period running, so that apatent infringement action remains admissible for acts committed during the last five years, even where the disputed exploitation began well before. Limitation reduces the basis for compensation more often than it bars the action: a patent holder who has been slow to act can still stop ongoing acts, but loses compensation for the time-barred period.

Proving the starting point

A defendant who pleads limitation must establish the date on which the patent holder became aware of the facts. The evidence used includes the product's market launch, its presentation at a trade fair, an earlier warning letter, negotiation correspondence or a licence offer. The report of a saisie-contrefaçon carried out several years earlier often provides the most direct evidence, which calls for a close look at the time allowed to pass between the findings and the writ.

Limitation before the UPC

Article 72 of the Agreement on a Unified Patent Court also provides for five years, from the date on which the claimant became aware, or had reasonable grounds to become aware, of the last fact relied on. The rule applies to all actions brought before the Unified Patent Court. The same exploitation may therefore be subject to two different computations depending on the court seised, the choice of forum determining the applicable period.

Key points

Limitation is debated first as to its starting point, then as to the scope of the acts that remain compensable. A patent holder who delays after discovering the infringement takes a financial risk, not a procedural one. The defendant, for its part, should document early on what its opponent knew and since when.

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This glossary entry is general in scope and does not constitute legal advice.

Dhenne Avocats litigates patent disputes before the Paris Judicial Court, the Paris Court of Appeal and the Unified Patent Court. Where the question arises in a real case, the useful moment is almost always before proceedings are issued.

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