No such bill or sign board shall be erected, maintained or used upon, along or within fifty feet (50') of the street line of any street bordering upon any public park, nor in any block in the city in which two-thirds (2/3) of the buildings on both sides of the street in such block are devoted exclusively to residence purposes, unless the consent in writing is obtained from the owners, or their agents, of two-thirds (2/3) of the property fronting upon both sides of such street, according to frontage, in such block in which such bill or sign board is proposed to be erected or used. Such written consent shall accompany the application for license for such bill or sign board. (R.O. 1959, Ch. 10, Art. 2, Sec. 6)