No building or addition thereto, constructed after the effective date of this chapter, and no addition to a previously existing building shall be occupied, and no land vacant on the effective date of this chapter shall be used for any purpose until a certificate of occupancy has been issued by the office of the director of public services. No change in a use, other than that of a permitted use in a district, shall be made until the certificate of occupancy has been issued by the office of the director of public services. Every certificate of occupancy shall state that the use or occupancy complies with all the provisions of this chapter.
('69 Code, App. A, § 10.4-1)