Subsequent to the effective date of this chapter, no change in the use or occupancy of land in the D Commercial Districts, nor any change of use or occupancy in an existing building in the D Commercial Districts, shall be made, nor shall any new building except garage and accessory buildings be occupied for any purpose until a certificate of occupancy has been issued by the Zoning Chairman. Every certificate of occupancy shall state that the new occupancy complies with all provisions of this chapter.

No permit for excavation for, or the erection or alteration of, a building shall be issued before the application has been made for a certificate of occupancy and compliance, and no building or premises shall be occupied until that certificate and permit are issued.

A record of all certificates of occupancy shall be kept on file in the office of the Zoning Chairman, and copies shall be furnished on request to any person having a proprietary or tenancy interest in land or in a building affected by such certificate of occupancy.

Certificates of occupancy shall be required for all nonconforming uses of land or buildings created by the passage of this chapter. Application for such certificate of occupancy for nonconforming uses shall be filed with the Zoning Chairman by the owner or lessee of the land or building occupied by such nonconforming use within two years from the effective date of this chapter. It shall be the duty of the Zoning Chairman to issue a certificate of occupancy for a nonconforming use.