It is hereby declared to be a nuisance for any person to set up, or cause to be set up, over any street, alley or sidewalk any awnings less than eight feet (8') high or to suspend any awning or any sign, sign box or fixture over any street or sidewalk lower than eight feet (8') above the same or to suspend any merchandise or other article in front of any building and more than two feet (2') from the wall thereof so that any part of the same shall be less than eight feet (8') above the sidewalk or ground. This Section shall not apply to awnings, etc., already erected and in place, but shall apply to any of the aforesaid which shall hereafter be erected. (R.O. 1929 Ch. XXVI § 1)