Industrial Property Law

The invalidation of a patent entails its extinction as of the date of filing of the patent application , and the retroactive cancellation of contracts relating to the patent . The supplementary protection certificate based on this patent is also revoked (Article L. 613-28 IP Code).

There has been some hesitation in the case law as to what to do about a final judgment for patent infringement when the patent is subsequently the subject of an annulment decision. Initially, the Court of Cassation held that the res judicata effect of the judgment ruling on the validity of the patent and its infringement justified a Court of Appeal in denying a motion for a stay of judgment on the liquidation of the harm resulting from the infringement as a result of a pending third-party action for revocation of the patent in question . 

However, in a subsequent judgment, the Court ruled that a patentee cannot rely on the res judicata effect of a judgment of conviction for patent infringement, if a subsequent fact or act amends the situation previously recognized by the court. Thus, since the invalidity of a patent renders it null and void as of the date of filing of the patent application, when the judgments finding infringement and subsequent revocation of the patent are final, the ongoing proceedings to determine the amount of damages owed by the infringer are devoid of any legal basis. The judgment ruling on the award of damages must be reversed, and any advance paid must be returned . Finally, the Court of Cassation clarified its position in a judgment handed down by the plenary session. It held that if an infringer is convicted under a final judgment, the subsequent annulment of the patent on which the infringement action was based does not entitle him to restitution of the sums paid in execution of the conviction for infringement. In this case, the res judicata effect of the infringement ruling overrides the absolute retroactive effect of the patent revocation .

Furthermore, a Court of Appeal cannot convict an undertaking of infringement where the Court of Cassation has, in another case, quashed two judgments invalidating the patent .

Cass. com. June 12, 2007, LawLex202200003330JBJ.

CA Paris, 5 April 2019, LawLex202300002986JBJ, which nevertheless clarifies that the invalidity of a license agreement resulting from the revocation of the patent to which it relates does not, regardless of the grounds for such nullity, have the consequence of retroactively depriving the licensee of any basis for the remuneration payable to him or her in return for the prerogatives effectively enjoyed.

Cass. com. 27 January 1998, LawLex202200003311JBJ.

Cass. com., 12 juin 2007, LawLex202200003330JBJ.

Cass.,  Ass. plén., 17 February 2012, LawLex202200003310JBJ.

Cass. com, 3 March 2009, LawLex202200003312JBJ, which cited its two judgments handed down on the same day, upholding the revocation of claims, and quashing the Court of Appeal judgment declaring them valid and infringing.

369. Retroactive effect