La. R.S. 33:4347

All suits to contest any election held under this Sub-part shall be brought within thirty days after the promulgation of the returns, and after that date no suit shall be brought to contest any such election or the promulgation of the returns thereof for any cause. If the validity of any election held under the provisions of this Sub-part is not raised within the thirty days herein prescribed the legality of the election shall be conclusively presumed, and no court thereafter shall have authority to inquire into its legality.