It shall be unlawful for any owner to use or permit the use of any building or part thereof, hereafter erected, altered, converted or enlarged, wholly or in part, until a Certificate of Occupancy, applied for at the time of application for a building permit, shall have been issued by the Construction Official. Such Certificate shall show that such building, or part of a building, and the proposed use thereof, conforms to the requirements of this chapter. It shall be the duty of the Construction Official to issue a Certificate of Occupancy only when he is satisfied that the building, or part of a building, and the proposed use thereof so conform.