2.26 In which language must the international application be filed? 

2.26.001The international application, i.e. the request, description, claim(s), drawing(s) and abstract, must be filed with the EPO as receiving Office in English, French or German. An international application filed in another language will be forwarded to the IB to act as receiving Office instead of the EPO. This means that there is no possibility to file an application with the EPO as receiving Office in any other language than is provided under Article 14(1) EPC.

2.26.002If an application is filed with the EPO as receiving Office in one of its official languages, that language will be the language of the proceedings which may not be changed either during the international phase or on entry into the European phase (see points 5.1.013-point 5.1.014). However, with the exception of amendments and corrections to the application, for which the language of the international application must be used, any other correspondence with the EPO may be in any of the EPO's three official languages.

2.26.003For applications filed on or after 1 July 2022 which contain a sequence listing, the EPO as receiving Office not only accepts sequence listings with language-dependent free text in English or in the same language as used in the international application (French or German) but also permits language-dependent free text to be filed in both English and any other language within a single sequence listing.