The return clause inserted in the deed of gift allows the donor to recover ownership of the donated property, either in the event that the beneficiary of the donation dies before him, or in the event of the predecease of the beneficiary and his descendants (art. 951 Civil Code).
It is then the very existence of the donation that is called into question. The donor recovers the donated property, including when the recipient of the donation had sold or given it away. Similarly, the guarantees that the donee could have granted on the property (e.g., mortgage) are deemed never to have been taken.