La. R.S. 47:1546

The notice or subpoena requiring a person to attend a hearing authorized by this Sub-title, to be examined, or to answer any questions or to produce any books, records, papers, vouchers, accounts or documents, shall be given by the collector or any of his authorized assistants, either through personal service on the person and endorsement of such service on the reverse of a copy of such notice, or by sending a notice by registered mail to the last known address of such person. The mailing of the notice shall be presumptive evidence of its receipt by the person to whom it was addressed.