Penal Code 26230 (a) A person granted a license to carry a pistol, revolver, or other firearm capable of being concealed upon the person pursuant to Section 26150, 26155, or 26170 shall not carry a firearm on or into any of the following: (22) A church, synagogue, mosque, or other place of worship, including in any parking area immediately adjacent thereto, unless the operator of the place of worship clearly and conspicuously posts a sign at the entrance of the building or on the premises indicating that licenseholders are permitted to carry firearms on the property. Signs shall be of a uniform design as prescribed by the Department of Justice and shall be at least four inches by six inches in size. (26) Any other privately owned commercial establishment that is open to the public, unless the operator of the establishment clearly and conspicuously posts a sign at the entrance of the building or on the premises indicating that licenseholders are permitted to carry firearms on the property. Signs shall be of a uniform design as prescribed by the Department of Justice and shall be at least four inches by six inches in size.