La. Stat. tit. 17 § 1372
School sub-districts shall not be created within a school district except as provided in this Section.
A parish school board may, with the approval of the Louisiana State Bond and Tax Board, create a school sub-district within a district whenever the population of such district has suddenly increased by reason of industrial or oil development.
Bond issues and special taxes may be voted in such sub-district in the manner provided by law for school districts.
After the creation of a school sub-district as provided in this Section, the property therein shall be subject to taxation for the retirement and payment of bonds and special taxes previously voted and levied in the old district, and for the retirement and payment of bond issues and special taxes thereafter voted by the qualified voters of the sub-district.
La. R.S. § 17:1372