California Code, Penal Code - PEN § 647e

(a) A city, county, or city and county may by local ordinance provide that no person who has in his or her possession any bottle, can or other receptacle containing any alcoholic beverage which has been opened, or a seal broken, or the contents of which have been partially removed, shall enter, be, or remain on the posted premises of, including the posted parking lot immediately adjacent to, any retail package off-sale alcoholic beverage licensee licensed pursuant to Division 9 (commencing with Section 23000) of the Business and Professions Code, or on any public sidewalk immediately adjacent to the licensed and posted premises.  Any person violating any provision of such an ordinance shall be guilty of an infraction.

(b) As used in subdivision (a), “posted premises” means those premises which are subject to licensure under any retail package off-sale alcoholic beverage license, the parking lot immediately adjacent to the licensed premises and any public sidewalk immediately adjacent to the licensed premises on which clearly visible notices indicate to the patrons of the licensee and parking lot and to persons on the public sidewalk, that the provisions of subdivision (a) are applicable.  Any local ordinance adopted pursuant to this section shall require posting of the premises.

(c) The provisions of this section shall not apply to a private residential parking lot which is immediately adjacent to the posted premises.

Nothing in this section shall affect the power of a county or a city, or city and county, to regulate the possession of an opened alcoholic beverage in any public place or in a place open to the public.