Each applicant for a license under this chapter to conduct an auction sale shall permit and provide for an official observer representing the city to be in attendance at all times during such auction sale for observation and investigation for the purpose of seeing that no personal property is sold except that which is included in the inventory filed with the city clerk. The applicant shall pay to such official observer the sum of seven dollars and fifty cents per day, in advance, for each day such auction is held. (Prior code § 3-14)