La. Public Health and Safety § 40:1576
Any order for removal or remedying issued pursuant to R.S. 40:1575 may be served upon the occupant of the premises to which it is directed by delivering a copy to the occupant personally or by registered or certified mail, or to any person in charge of the premises. If no person is found upon the premises, the order may be served by affixing a copy thereof in a conspicuous place on the door at the entrance to the premises. Whenever it is necessary to serve an order upon the owner of the premises, it may be served either by delivering a copy to the person as herein provided or, if the owner is absent from the jurisdiction of the officer making the order, by mailing the copy to the owner's last known post office address.
La. Public Health and Safety § 40:1576