Article 993 of Civil Code

1 - A mortgage shall not be effective against a third party unless it is registered before that third party acquires a right in rem over the immovable, without prejudice to the provisions established in bankruptcy. 2 - Neither the assignment of a right secured by a registered mortgage, nor the right arising from a person's subrogation to the creditor in that right by operation of law or by agreement, nor the relinquishment of the mortgage's rank in favor of another creditor may be invoked against third parties unless it is annotated in the margin of the original registration.