Patent opposition proceedings


The opposition proceedings are introduced to strengthen the legal security of the patent and to simplify for third parties the proceedings which can lead to the cancellation of the patent.

The opposition proceedings, which takes place before the INPI, applies to patents for invention, for which mention of grant was published in the Official Bulletin of Industrial Property (BOPI) after April 1, 2020.

These proceeding aim at obtaining the revocation, in whole or in part, of a French patent. The period for filing an opposition is 9 months from the publication of the mention of grant of the patent in the BOPI. Due to this time constraint, these proceedings cannot fully replace the invalidity proceedings before the Tribunal de Grande Instance of Paris.

Anyone, except the patent owner, can file an opposition without having to prove an interest to act. This therefore includes the possibility for a straw man to initiate the opposition proceedings.


Find below the details of the legal provisions governing these new opposition proceedings.

The opposition must be based on grounds of:

  • lack of novelty, inventive step and/or industrial application,
  • exclusion from patentability (surgical, therapeutic, and diagnostic methods, animal breeds and plant varieties, computer programs, etc.),
  • insufficient description,
  • extension of the subject-matter of the patent beyond the content of the patent application as filed, and if necessary, in the event of claims’ amendments during opposition proceedings, extension of the claimed subject-matter beyond the scope of the claims as granted.

The filing of an opposition involves the payment of a fee (today € 600).

The opposition is a "contradictory" procedure involving the possibility for a party to respond to the other party's observations, and comprising three phases:

  • examination of the admissibility of the opposition, which should last 2 months;
  • investigation of the opposition including a debate between the parties and between the parties and INPI, which should last from 8 to 11 months;
  • decision of the Director General of INPI on the opposition, which should last 4 months.

The opposition is deemed rejected if the Director General of INPI does not rule on the opposition within 4 months from the end of the investigation phase.


( - S'opposer à un brevet délivré à compter du 1er avril 2020

During the investigation phase, the INPI notifies the opposition to the Patentee and specifies a deadline for responding, including the possibility of modifying the set of claims, and if necessary, the description and the drawings.

Subsequently, based on the Opposition brief and the Patentee's response, the INPI issues an investigation opinion which is notified to the parties, offering them the opportunity to respond to it. Several written exchanges between the parties can then take place.

During this phase, the Patentee can modify the description, the claims and the figures, and also file auxiliary requests.

Oral proceedings are held if requested by one of the parties or if the INPI considers it necessary. The investigation phase is closed either on the day of the oral proceedings or at the end of the time limit set for the parties for the last exchange. The latter may be the investigation opinion if none of the parties responds to it.

The investigation phase or the decision phase can be suspended:

  • Upon written request of any person proving an action to claim ownership of the patent brought before the court;
  • After a court is seized of a request for nullity thereof;
  • At the initiative of the INPI, when waiting for information and elements likely to have an impact on the outcome of the opposition or the situation of the parties.

The investigation phase may also be suspended upon joint request of the parties for a period of 4 months, renewable twice.

The opposition proceedings can be closed at any time:

  • After withdrawal of the oppositions;
  • After invalidation of the patent by a final court decision;
  • After waiving by the Patentee of the claims targeted by the opposition;
  • After the effects of the opposed Patent have ceased unless the Opponent proves a legitimate interest in obtaining an opposition decision.

The opposition proceedings prevail over the limitation proceedings.

 At the end of the decision phase, the Director General of INPI issues a reasoned decision, having an absolute and retroactive effect from the filing date of the Patent. The decision is notified to all the parties. The decision is recorded in the national patent register.

The decision can be:

  • total or partial revocation of the patent. Partial revocation only seems possible if only part of the claims is the subject of the opposition proceedings;
  • maintaining the patent in an amended form;
  • maintaining the patent as granted.

The decision of the Director General of INPI with regard to the opposition is subject to appeal to the Court of Appeal of Paris. The appeal is suspensive and can lead to the review of the decision.

The decisions of the Court of Appeal can be appealed in cassation.