It shall be unlawful for any person to paste, post, paint, print or nail any handbill, sign, poster, advertisement, or notice of any kind on any curbstone, flagstone, or any other portion or part of any sidewalk, or upon any tree, lamppost, utility pole, hydrant, or upon any private wall, door, or gate without the consent, in writing, of the owner of the wall, door or gate; provided, however, that this Section shall not prevent posting by proper Village and County officials of election signs, polling place signs and other signs or placards necessary under the law to the conduct of elections, except they may not be attached to a tree.