Louisiana Civil Code Tit. III, Art. 1829. Subrogation by operation of law

(1) In favor of an obligee who pays another obligee whose right is preferred to his because of a privilege, pledge, mortgage, or security interest;

(2) In favor of a purchaser of movable or immovable property who uses the purchase money to pay creditors holding any privilege, pledge, mortgage, or security interest on the property;

(3) In favor of an obligor who pays a debt he owes with others or for others and who has recourse against those others as a result of the payment;

(4) In favor of a successor who pays estate debts with his own funds; and

(5) In the other cases provided by law.