La. Stat. tit. 38 § 1787
Before bonds of any district are issued hereunder, the governing authority shall investigate and determine the regularity of the proceedings. The resolution authorizing the bonds may direct that they shall contain the following recital:
"It is certified that this bond is authorized by and is issued in conformity with the requirements of the Constitution and statutes of this State," and the recital shall be deemed to be an authorized declaration by the governing authority of the district, and to import that the debts are incurred and the bonds are issued for purposes authorized by the Constitution and statutes, that all the proceedings therefor are regular and all acts, conditions and things required to exist, happen and be performed precedent to and in the issuance of the bonds, have existed, happened, and have been performed in due time, form, and manner as required by law; that the amount of the bonds, together with all other indebtedness does not exceed any limit or limits prescribed by the constitution and statutes of this state and that an election has been duly and legally held and the incurring of the debt and the issuing of negotiable bonds therefor authorized by vote of a majority in number and amount of the property taxpayers qualified to vote under the constitution and laws of this state, who voted at an election regularly called and held for the purpose, after notice published or posted in the manner required by law. If any bond is issued containing the recital it shall be conclusively presumed that recital constructed according to the import hereby declared is true and neither the district nor any taxpayer thereof shall be permitted to question the validity or regularity of the obligation in any court or in any action or proceeding.
La. R.S. § 38:1787