The obligation to adjudicate on fault
When deciding a divorce, the court must indicate which spouse is to blame for the breakdown of the marriage. If the parties do not submit an unanimous request to not adjudicate on fault, the court is obliged to determine whether and which spouse is at fault for the breakdown of the marriage. This means that the court decides on guilt ex officio, and not at the request of the spouses.
Appeal and prohibition of reformationis in peius
What if only one of the parties lodges an appeal against the divorce judgment in the part concerning the fault of the breakdown of the marriage? In civil proceedings, the rule is that the court may not set aside or amend the judgment to the detriment of the appellant, unless the opposing party also files an appeal.
However, this rule does not apply in the present case. The court of second instance may ex officio adjudicate on the guilt of the breakdown of the marriage also to the detriment of the spouse who lodged the appeal. This was stated by the Supreme Court in its judgment of 19 January 2005, reference number V CK 364/04.
In practice, this means that if, for example, the court of first instance decides that neither party is guilty of the breakdown of the marriage, then the appeal is brought by only one party, then the court of second instance may adjudicate to the detriment of the appellant, e.g. decide that both parties are guilty.