The City Manager shall appoint an inspector for every auction sale conducted in the City, except those exempt under Section 806.11, who shall be at all times on the premises while such sale is in progress. The inspector shall be given a copy of the inventory by the City Clerk and shall, as each article is sold, check each item off the inventory. If any article is offered for sale which does not appear on the inventory, the inspector is authorized to forbid the sale of such article, and if the auctioneer refuses to comply with such request, the inspector may forthwith stop the sale until the auctioneer furnishes satisfactory proof that such article was included in the inventory. The owner or auctioneer shall pay or cause to be paid to the City Treasurer a sum determined by the City Commission, in advance, for each day such auction is to continue, for the services of such inspector, but such payment may be made on the day of the sale if made before the hour of its commencement. If the sale does not run for a full day of eight hours, the owner shall pay a sum determined by the Commission for each hour the inspector is on duty.