La. Civ. Code art. 186
Current with operative changes from the 2024 Third Special Legislative Session
If a child is born within three hundred days from the day of the termination of a marriage and his mother has married again before his birth, the first husband is presumed to be the father.
If the first husband, or his successor, obtains a judgment of disavowal of paternity of the child, the second husband is presumed to be the father. The second husband, or his successor, may disavow paternity if he institutes a disavowal action within a peremptive period of one year from the day that the judgment of disavowal obtained by the first husband is final and definitive.
La. C.C. § 186