An applicant claiming priority shall file a copy of the previous application within sixteen months of the earliest priority date claimed. This copy and the date of filing of the previous application shall be certified as correct by the authority with which that application was filed.
The copy of the previous application shall be deemed to be duly filed if a copy of that application available to the European Patent Office is to be included in the file of the European patent application under the conditions determined by the President of the European Patent Office.
Where the previous application is not in an official language of the European Patent Office and the validity of the priority claim is relevant to the determination of the patentability of the invention concerned, the European Patent Office shall invite the applicant for or proprietor of the European patent to file a translation of that application into one of the official languages within a period to be specified. Alternatively, a declaration may be submitted that the European patent application is a complete translation of the previous application. Paragraph 2 shall apply mutatis mutandis. If a requested translation of a previous application is not filed in due time, the right of priority for the European patent application or for the European patent with respect to that application shall be lost. The applicant for or proprietor of the European patent shall be informed accordingly.
See decisions of the President of the EPO, Special edition No. 3 OJ EPO 2007, B.2 and OJ EPO 2012, 492.
See also the decision of the President of the EPO on the filing of priority documents (OJ EPO 2018, A78) and the notice from the EPO concerning priority document exchange via WIPO Digital Access Service (OJ EPO 2018, A79).