No person shall encroach upon or in any way obstruct or occupy any street, alley, sidewalk, public ground or land dedicated to public use by placing, building or erecting or causing to be placed, built or erected in, upon or over such street, alley, sidewalk, public ground or land dedicated to public use, any fence, building or structure of any kind whatever, or permit the same to remain when placed, built or erected. However, nothing herein shall prevent signs, awnings and canopies constructed, erected and maintained in accordance with the provisions of the City ordinances. (1964 Code §519.08)