Government Code § 38774

The legislative body may:

(a) Regulate the exhibition, posting, or carrying of banners, placards, posters, cards, pictures, signs, or advertisements in or on the street, or on or upon buildings, fences, billboards, or other structures; or on or upon any pole in any sidewalk, alley, street, lane, court, park, or other public place.

(b) Regulate the suspension of banners, flags, signs, advertisements, posters, pictures, or cards across, or over any sidewalk, alley, street, lane, court, park, or other public place, or such suspension from fences, poles, houses, or other structures.