La. Revenue and Taxation § 47:338.77
For a period of thirty days from the date of the publication of the resolution authorizing bonds hereunder and pledging and dedicating sales tax revenues thereto, any person in interest may contest the legality of the bonds provided for or the tax, the proceeds of which are so pledged and dedicated, for any cause, after which time no one shall have any cause or right of action to contest the legality, formality or regularity of the proceedings, the tax, or bond authorization, for any cause whatsoever. If the question of the validity of any proceedings, tax, or bond authorization provided for under the provisions of R.S. 47:338.48 through 338.78 is not raised within the thirty days, the authority to issue the bonds, the regularity thereof, the validity of the tax pledged and dedicated to provide for the payment of principal and interest, and the enforceability of the pledge thereof, shall be conclusively presumed, and no court may inquire into such matters. If any resolution is adopted or proceedings had more than thirty days after the publication of the resolution authorizing the bonds and pledging and dedicating the sales tax revenues, no contest, action or proceeding to question the validity or legality of the resolution, or proceedings so adopted, shall be begun in any court by any person for any cause whatsoever after the expiration of thirty days from the date wherein the resolution was adopted or proceedings had.
La. Revenue and Taxation § 47:338.77