In essence, parties have the same duties as witnesses—i.e. the duty to testify, the duty to appear and the duty to take an oath. However, unlike witnesses, the appearance and testimony cannot be compelled, which means that a failure to appear or a refusal to testify is only taken into account in the weighing of evidence. As a rule, this will be disadvantageous for the non-testifying party, as it increases the probability that the recognizing court will regard the assertions of the opposing party as proven.
There is an exception in marriage proceedings. Here, the obligation to appear can be enforced, for example by threatening and imposing an administrative fine and compulsory appearance.
Also, the right as a party to refuse to testify is broadly similar to that of a witness.
However, there is a significant difference with regard to the punishability of false statements. In the case of a witness, false testimony without being sworn is punishable, but in the case of an examination of a party, only false testimony under oath is punishable.