Rule 120
Hearing by a competent national court

(1) A party, witness or expert who is summoned before the European Patent Office may request the latter to allow him to be heard by a competent court in his country of residence. If this is requested, or if no reply is received within the period specified in the summons, the European Patent Office may, in accordance with Article 131, paragraph 2, request the competent court to hear the person concerned.

(2) If a party, witness or expert has been heard by the European Patent Office, the latter may, if it considers it advisable for the testimony to be given under oath or in an equally binding form, issue a request under Article 131, paragraph 2, to the competent court in the country of residence of the person concerned to re-examine his testimony under such conditions.

(3) When the European Patent Office requests a competent court to take evidence, it may request the court to take the evidence under oath or in an equally binding form and to permit a member of the department concerned to attend the hearing and question the party, witness or expert, either through the intermediary of the court or directly.