California Code, Penal Code - PEN § 318.6

(a) Nothing in this code shall invalidate an ordinance of, or be construed to prohibit the adoption of an ordinance by, a city or county, if that ordinance relates to any live acts, demonstrations, or exhibitions occurring within adult or sexually oriented businesses and involve the exposure of the genitals or buttocks of any participant or the breasts of any female participant, and if that ordinance prohibits an act or acts which are not expressly authorized or prohibited by this code.

(b) For purposes of this section, an “adult or sexually oriented business” includes any establishment that regularly features live performances which are distinguished or characterized by an emphasis on the exposure of the genitals or buttocks of any person, or the breasts of any female person or sexual activities that involve the exposure of the genitals or buttocks of any person, or the breasts of any female person.

(c) The provisions of this section shall not be construed to apply to any adult or sexually oriented business, as defined herein, that has been adjudicated by a court of competent jurisdiction to be, or by action of a local body such as issuance of an adult entertainment establishment license or permit allowing the business to operate on or before July 1, 1998, as, a theater, concert hall, or similar establishment primarily devoted to theatrical performances for purposes of this section.

(d) This section shall not be construed to preempt the legislative body of any city or county from regulating an adult or sexually oriented business, or similar establishment, in the manner and to the extent permitted by the United States Constitution and the California Constitution.