Avoidance takes effect retroactively.
Civil Code
2015 English source edition · Current applicability not established.
This is the 2015 English-language edition attributed in its front matter to the Ministry of Justice. Eri Atlas has not independently verified the translation, later changes, or whether the text is currently in force. Nine passages are incomplete in the available scan and are identified where they occur.
Article 1391
Retroactive Effect of Avoidance · Preserved transcription; page attribution imported from the source collection. Verify against the original.
On avoidance either party may claim restitution of whatever it has supplied under the contract or the part of it avoided, provided that it concurrently makes restitution of whatever it has received under the contract or the part of it avoided or, if it cannot make restitution in kind, it makes an allowance for what it has received.