No person shall erect upon any street, alley or sidewalk any signpost, sign or post of any description, except such as may be erected by the city for public purposes or by persons or corporations thereto authorized by ordinances of the city, nor shall any sign be placed or constructed more than four feet from the lot line of the street nor extend more than four feet from the building into the street, and no sign, showcase, stand or display of goods or merchandise of any description shall be attached to or fastened to the sidewalk or allowed to stand thereon and extending more than four feet from the lot line into the street, nor suspended within eight feet from the sidewalk when attached to any building.  No awnings of any kind shall be erected upon the sidewalks nor shall any awnings extend into the street from any building except the same be folding cloth awnings.  No awning shall be suspended less than eight feet above the sidewalk.