Prior to the sale or transfer or equitable ownership of any real estate within the City of Clayton, the current owner or his agent shall schedule an exterior inspection to obtain a pre-sale exterior occupancy inspection. An inspection must also be conducted upon an occupancy change, but in no case more than once during any twelve (12) month period. If no exterior violations exist upon the date of inspection a certificate of occupancy shall be issued. If exterior violations exist upon the date of inspection a certificate of occupancy will not be issued until all violations are corrected and brought into compliance. No person shall sell or receive a commission or fee from the sale or long-term lease of any real property in the City of Clayton without a valid certificate of occupancy in effect. Apartment complexes of more than four (4) units shall are exempt from this program.