Louisiana Civil Code Tit. II, Art. 1593. Exception to rule of testamentary accretion

If a legatee, joint or otherwise, is a child or sibling of the testator, or a descendant of a child or sibling of the testator, then to the extent that the legatee's interest in the legacy lapses, accretion takes place in favor of his descendants by roots who were in existence at the time of the decedent's death. The provisions of this Article shall not apply to a legacy that is declared invalid or is declared null for fraud, duress, or undue influence.