Kernrechtsfrage
Whether the restitution duty after successful avoidance of a contract is governed by federal or cantonal law.
Extrahierter Entscheid
The content of the restitution obligation is governed by cantonal law, not federal law.
Extrahierte Begründung
Because the dispute concerns the manner and scope of restitution after avoidance for prejudice to creditors, Art. 889 OR leaves the matter to cantonal law.