5.1.2 Individual cases
With regard to principles of procedural law generally recognised in the contracting states, a party relying on Art. 125 EPC and asserting that German law allows for the revision of a decision of a court of final jurisdiction in the case of a fundamental procedural violation, will also have to produce evidence that such a procedural principle exists in most EPC contracting states and is therefore "generally recognised" for the purpose of Art. 125 EPC 1973 (T 843/91 date: 1993-08-05, OJ 1994, 832). Following on from that, another board stated in T 833/94 that, when the evidence offered did not directly indicate the truth or falsity of the fact in issue, but required knowledge of the national law and patent practice, such law and practice had to be proved, as did any other fact on which a party based its arguments.
In J 14/19, the issue of when national proceedings became pending was to be assessed under German procedural law. At the EPO, German law was to be treated as foreign law for conflict-of-law purposes. Where the EPO was called on to apply foreign law, it has to do so within the overall context of the foreign legal system, wherever possible. When interpreting the foreign law to be applied, it was not bound by the case law of national courts, but if it was aware of the case law of the highest national court, it should consider and evaluate it in coming to its decision. The appellant had referred to German legal commentaries in support of its interpretation of German law. However, they were not official publications and did not form part either of the law created by legislation or of the case law, so they were not, as such, to be taken into account by the EPO when applying foreign law. Moreover, parties and their representative could not assume that the boards of appeal had access to all the legal literature of all the EPC contracting states, particularly when that literature was unrelated to patent law. The legal commentaries cited by the appellant in relation to the German Code of Administrative Court Procedure were therefore taken into account only to the extent that they had been produced.
The Enlarged Board in G 4/19 concluded that there was a real and effective agreement that the EPO should prohibit double patenting by taking into account principles of procedural law generally recognised in the contracting states, i.e. by a direct application of Art. 125 EPC. At the time of signing of the EPC, the statement made by the delegations in this respect had to be taken as proof that the principle of the prohibition on double patenting was a generally recognised principle in the contracting states. No information had been brought to the Enlarged Board's attention, nor had it been argued, that this situation might have changed, for example through the accession of new contracting states, or as a result of more recent legislation in the contracting states.
The board in ex parte case T 1473/13 (stay of proceedings – pending complaints before the German Federal Constitutional Court (FCC) regarding a possible lack of judicial independence of the members of the boards of appeal) was of the opinion that the case law (T 833/94, T 74/00, T 517/14) meant that a board was not required to make investigations of its own on a party's case but could still do so where it deemed it appropriate, at least in ex parte cases. The appellant had made assertions without providing details and/or explanations as to, for example, whether the FCC had jurisdiction under German constitutional law over acts of the EPO relating to Germany, and, if so, what the scope of that jurisdiction was and what powers were vested in the FCC to exercise it. The board considered it appropriate to cover the essentials of this point of law of its own motion. This was because if the German FCC did not have jurisdiction over acts of the EPO boards of appeal, any further discussion of the fourth auxiliary request would be moot.