The following contracts are inexistent and void from the beginning:
(1) Those whose cause, object or purpose is contrary to law, morals, good customs, public order or public policy;
(2) Those which are absolutely simulated or fictitious;
(3) Those whose cause or object did not exist at the time of the transaction;
(4) Those whose object is outside the commerce of men;
(5) Those which contemplate an impossible service;
(6) Those where the intention of the parties relative to the principal object of the contract cannot be ascertained;
(7) Those expressly prohibited or declared void by law.
These contracts cannot be ratified. Neither can the right to set up the defense of illegality be waived.