No producer or grower, or his or her agents or employees, selling in the city, farm or garden products or fruits grown by him or her in the state shall be required to pay any license fee or occupation tax imposed by any ordinance, and he or she, his or her agents or employees are exempted from the payment of any such fees or taxes, or the securing of a license. The city clerk may require an affidavit of any person claiming an exemption hereunder of the facts tending to show such exemption. (Prior code § 6-105)