Applying statutes of limitations to patent revocations in France:
Running solves nothing: you have to start moving at the right moment… but when?
by Pauline Debré and Jean-François Merdrignac, Linklaters Paris

Equity aids the vigilant, not the ones who sleep over their rights (iura vigilantibus, non dormientibus prosunt). This is also true for claimants in a patent revocation action. The nullity of a patent can be raised either as a main claim, in a patent revocation action, or, more often, as a counterclaim to a patent infringement action.

Even if some authors still consider that time limitation should not apply at all, the Paris Courts have now clearly admitted that a patent revocation action is subject to the main time limitation period of five years, provided for in Article 2224 of French Civil Code. The starting point of this five-year period is the day on which the holder of a right knew or should have known the facts enabling him/her to exercise his/her right.

The question has arisen then how to determine this starting point. The Paris Courts have put forward three alternatives.

The entire contribution can be read here.

The case law (in French) referred to in the article can be read here.