La. R.S. 25:212

A public library under this Part shall be created by an ordinance regularly passed and adopted by the police jury of the parish, or other governing authority thereof, and the municipal council or other governing authority of such municipality. All parish libraries shall be established at the parish seat and the municipal libraries within the corporate limits of the municipality so creating and establishing them. Provided that branch libraries may be established and maintained by either a parish or municipal library as the public demands require.