It is unlawful for any person to obstruct any sidewalk within the city or in any manner hinder or interfere with the free passage of other persons on it, to the extent of more than one-fourth of the width of such sidewalk, such width to be measured from the line of the building, fence or other structure adjacent to it; provided that such occupancy of any portion of the sidewalk may only be temporarily permitted when granted by a written permit of the city council. (Ord. 535 § 1, 1996)