Art. 133 and 134 EPC together with R. 152 EPC and the Decision of the President of the EPO dated 12 July 2007 on the filing of authorisations (OJ SE 3/2007, 128) provide a complete, self-contained code of rules of law on the subject of representation in proceedings established by the EPC. Art. 133 EPC lays down the general principles of representation. Art. 133(1) EPC stipulates that, subject to Art. 133(2) EPC, no person is compelled to be represented by a professional representative in proceedings established by the EPC. However, according to Art. 133(2) EPC, natural persons not having their residence in an EPC contracting state must be represented by a professional representative (Art. 134(1) EPC) or a legal practitioner (Art. 134(8) EPC) and act through him in all proceedings established by the EPC, other than in filing the European patent application (T 578/14).

The Guidelines for Examination in the EPO (November 2018 version) contain detailed information on the practice relating to representation, most notably in: A‑III, 2; A‑VIII, 1 and D‑I, 7. They also refer to the decisions of the EPO President dated 12 July 2007 (OJ SE 3/2007, A.3 and L.1.). Readers can find analyses of those decisions in, for example, T 267/08, J 8/10 and T 1744/09.