La. Stat. tit. 38 § 1792
Whenever debt has been incurred and bonds voted to be issued and a forced contribution or acreage tax levied as herein provided, any land owner having property situated within the limits of the district, during sixty days next following the publication of the proclamation of the result of the election, may contest the validity of the proceedings by suit or action in courts, after which the validity of the proceedings or the bonds authorized thereby to be issued and the tax levied or authorized to be levied, shall be absolutely incontestable for any cause whatever and no court shall have the jurisdiction to hear or determine the validity of the proceedings or the bonds. No board which is required to levy the tax shall be permitted to question its authority to do so.
La. R.S. § 38:1792