Article 42 - Retroactive effect of avoidance

(1) Avoidance takes effect retroactively.
(2) On avoidance either party may claim restitution of whatever is supplied under the contract or the part of it avoided, provided that he concurrently makes restitution of whatever he has received under the contract or the part of it avoided or, if he cannot make restitution in kind, he makes an allowance for what it has received.