Every sign must be attached and parallel to the face of the building and shall not extend further than 12 inches from the face of the building; provided, however, that where a sign extends more than three inches from the face of said building, no portion of said sign shall be closer than 10 feet to the ground level below said sign, and further provided that where a building has a permanent canopy or marquee constructed as an integral part of said building, a sign, as permitted in this section, may be placed on the front line of the marquee, provided that no part of said sign extends below or beyond the front edge of the canopy or marquee. For the purposes of administering this section, the permitted area of the sign on the canopy or marquee shall be determined by the area of the wall from which said canopy or marquee extends.