Cal. Lab. Code § 90

The Labor Commissioner, his deputies and agents, shall have free access to all places of labor. Any person, or agent or officer thereof, who refuses admission to the Labor Commissioner or his deputy or agent or who, upon request, willfully neglects or refuses to furnish them any statistics or information, pertaining to their lawful duties, which are in his possession or under his control, is guilty of a misdemeanor, punishable by a fine of not more than one thousand dollars ($1,000).