La. R.S. 25:744

An historic preservation district commission may be empowered by the local governing body to name or designate any site, location, structure or monument within the area served by the governmental unit as worthy of preservation whether within or outside the confines of an historic district and to exercise all other powers and functions of a landmarks commission, except that no historic district commission shall be empowered to act in a landmark capacity where its jurisdiction overlaps the authority of an existing landmarks commission pursuant to this Act.