Until 31 May 2023, German law prohibited double protection (referred to as “prohibition on double protection”) for national patents and European patents. Accordingly, it was not possible to obtain protection under a national patent for an invention in respect of which a European patent with the same priority and the same scope had been granted to the same inventor with effect in the Federal Republic of Germany. The national patent became ineffective if the inventor had been granted a European patent for the same invention that could not be revoked in opposition proceedings any more.
On 1 June 2023, fundamental amendments to the prohibition on double protection became effective.
However, under certain conditions, such double protection is subject to the objection to double demands (Article II section 18 of the Act on International Patent Conventions), which is a "protective mechanism for defendants". Defendants in infringement proceedings thus cannot be sued both under a national patent before national courts and under a European patent or a Unitary Patent before the Unified Patent Court.
Basically, since 1 June 2023, it has been possible to hold a national patent in addition to either a European patent or a European patent with unitary effect (referred to as "Unitary Patent") (see Article II section 8 of the Act on International Patent Conventions). Since then, the prohibition on double protection has applied only to European patents that are not subject to the exclusive competence of the Unified Patent Court due to an opt-out pursuant to Article 83(3) of the Agreement on a Unified Patent Court. The combination of a national patent and a European patent for which an opt-out has been declared is the only situation in which a national patent with an identical subject matter still loses its effect, that is, double protection cannot be obtained. However, if no opt-out declaration is made and the European patent is still subject to the competence of the Unified Patent Court, the national patent continues to have effect alongside the European patent.
In addition, there is still the option to apply for a German utility model at the same time or split off a German utility model from a European patent application effective in the Federal Republic of Germany.