La. Stat. tit. 25 § 218
The costs of establishing and maintaining a parish public library shall be borne by the entire parish including the incorporated towns therein and all taxes levied and assessed, whether general or special, for the establishment, support and maintenance of such parish public library shall be borne proportionately by all of the property of the parish including that within incorporated municipalities, unless in the ordinance creating the parish public library the municipality is expressly excluded because of its exemption from parochial taxation or because such municipality owns, maintains and operates its own public library, and in such cases will not be entitled to library service, except upon such terms and conditions as may be agreed upon as provided in R.S. 25:211. Nor shall the residents or taxpayers of such excluded municipality be counted in making up the number of petitioners required in R.S. 25:211 and 25:217.
La. R.S. § 25:218