It is unlawful for a person, firm or corporation to place, erect or maintain or to permit the placing, erecting, maintenance or existence of an encroachment upon, over or under any street, avenue, lane, alley, sidewalk, court, place, public way, public property or right-of-way after his permit has expired or after his permit has been revoked and the time specified in the notice from the city clerk for removal of the same has expired. (Ord. 412 §1, 1996; Ord. 60 §2(d), 1954).