In a German civil trial, a party’s own account is not ordinary evidence. Under § 445 of the Code of Civil Procedure, a party that has not fully proven its case with other evidence or has offered none, may ask the court to examine the opposing party.
Under § 448, the court may order a party to be examined only if the hearing and the evidence taken are not enough to convince it. Law teaching calls this a subsidiäres Beweismittel, a means of evidence used only when others fall short.
The Federal Court of Justice qualified this in 2017. A personal hearing of a party under § 141 is not formal evidence. Even so, the judge may in a given case believe the party’s statements over those of a witness.