Louisiana Civil Code Tit. II, Art. 1483. Proof of fraud, duress, or undue influence

A person who challenges a donation because of fraud, duress, or undue influence, must prove it by clear and convincing evidence. However, if, at the time the donation was made or the testament executed, a relationship of confidence existed between the donor and the wrongdoer and the wrongdoer was not then related to the donor by affinity, consanguinity or adoption, the person who challenges the donation need only prove the fraud, duress, or undue influence by a preponderance of the evidence.