No person shall abuse, deface or injure any street signs maintained on the streets by the city by throwing any rocks, stones or other hard substances against same, by scratching or defacing same in any manner, or otherwise injuring same in any manner, or injure or deface the posts upon which such signs are erected by throwing any rocks, stones or other hard substances against same or by scratching, cutting or defacing same in any manner. (Code 1941, Art. 140-16)