Priority right (patents)

Following the filing of a patent application in a member state of the Paris Union or of the World Trade Organization (WTO) (for example with the INPI), the applicant benefits from a period of 12 months, from that first application, to extend its protection in another WTO member state while keeping the date of the first filing. The right of priority in patent law is thus a legal principle that allows an inventor or an applicant to seek international protection of an invention while relying on the filing date of an earlier application in another country. More precisely, where the applicant files a patent application in a given country, it may claim priority for that application when filing a later patent application in another member country of the Paris Convention for the Protection of Industrial Property. That priority means that the filing date of the first application is deemed to be the filing date of the later application in the other country. This allows the applicant to obtain broader protection for the invention without losing the priority of the initial application. The right of priority is generally valid for 12 months from the filing date of the initial application, although the duration may vary according to national laws.

Key points

The twelve months of priority set the calendar of any international strategy: they determine the date at which the state of the art is assessed and govern the choice between national extensions and an international application. A disclosure made before the first filing remains citable, and a poorly documented priority claim may be challenged in litigation, with a direct effect on the validity of the title.

A poorly documented priority claim is paid for in litigation, often years later: the chain of title and the time limits are secured upstream, as part of our building a defensible patent portfolio service.