In decision G 4/08 (OJ 2010, 572), the Enlarged Board of Appeal ruled on the first referred question that if an international application has been filed and published under the PCT in one official language of the EPO, it is not possible, on entry into the European phase, to file a translation of the application into one of the other two EPO official languages, which would then become the language of the proceedings. Neither the EPC 1973 nor the EPC 2000 can be interpreted as allowing that. Nor is there any conflict between EPC and PCT provisions. On the second question, the Enlarged Board decided that EPO departments cannot use, in written proceedings on a European patent application or an international application in the regional phase, an EPO official language other than the language of proceedings used for the application under Art. 14(3) EPC.
Source: http://www.epo.org/law-practice/legal-texts/html/caselaw/2019/e/clr_vi_4.htm
Date retrieved: 17 May 2021