Opposition to a European patent

Opposition to the grant of a patent is the administrative procedure by which a third party asks the office that granted the title to revoke or limit it. It takes place before the office itself, not before a court. Opposition has long existed before the European Patent Office and, since the PACTE Act, before the INPI for French patents.

Opposition before the EPO

Any person may file an opposition within nine months of the publication of the mention of grant in the European Patent Bulletin, in accordance with Article 99 of the European Patent Convention. The grounds are exhaustively listed in Article 100: lack of patentability, insufficiency of description and extension of the subject matter beyond the application as filed. The opposition division may reject the opposition, revoke the patent or maintain it in amended form. Its decision takes effect in all designated states and may be appealed before a Board of Appeal. The rules are detailed on the website of the European Patent Office.

Opposition before the INPI

For French patents granted since 1 April 2020, Articles L. 613-23 et seq. of the French Intellectual Property Code open an opposition procedure within nine months of the publication of the grant. First, the grounds are lack of patentability, insufficiency of description and extension of subject matter. Second, the procedure is written, with an adversarial examination phase and a possible hearing. Third, the decision of the INPI may be challenged before the Paris Court of Appeal. The provisions can be consulted on Légifrance.

Interplay with court litigation

Opposition does not deprive third parties of the nullity action before the Paris Judicial Court or the Unified Patent Court. The proceedings may run in parallel, which raises questions of stays and consistency of positions. In practice, opposition is an economical way of attacking a title with multi-territorial effect before any litigation, and a central element of multi-jurisdictional patent litigation. The firm coordinates these proceedings with patent attorneys, as presented on the page patent litigation.

Key points

Opposition is the least costly way to attack a patent, but the window closes quickly: nine months from the mention of grant. After that, only invalidity before the courts remains, state by state or before the Unified Patent Court. The decision of the office has a centralised effect, which makes it a lever in negotiation as much as a means of defence.