How does the opposition procedure work?
Obtaining a European patent: the opposition procedure

The filing of the notice of opposition, within nine months of publication of the grant of the European patent, triggers the start of proceedings. As soon as the EPO receives the notice of opposition, the examiner notifies it to the patent proprietor and checks that the grounds for opposition mentioned in the notice are admissible ( règle 77 de la CBE , Dir. OEB D IV ).

After examination of the admissibility of the opposition, it is forwarded to the patent owner. The latter is invited to respond within four months. An extension of this period will only be granted in exceptional cases, upon duly motivated...