La. Stat. tit. 37 § 3130
Notwithstanding any provision of this Chapter to the contrary, an auctioneer may bid on behalf of an absentee bidder for the protection of a consignor or owner of property sold or offered for sale at an auction. Prior to the commencement of the auction, the auctioneer shall provide public notice of the right and intention of the auctioneer to bid by printing such notice in the auction catalogue, other printed matter on the auction, or any newspaper advertisements publicizing the event or by announcing at the opening of the auction the intention to bid. In addition to the requirement for prior notice of intention of the auctioneer to bid as provided herein, written notice of the intention of the auctioneer to bid at an auction shall be openly displayed on the auction premises during the auction. Failure to provide this notice or to make the announcement shall nullify the sale.
La. R.S. § 37:3130