Cal. Civil Code § 3339

The Legislature finds and declares the following: (a) All protections, rights, and remedies available under state law, except any reinstatement remedy prohibited by federal law, are available to all individuals regardless of immigration status who have applied for employment, or who are or who have been employed, in this state. (b) For purposes of enforcing state labor, employment, civil rights, consumer protection, and housing laws, a person’s immigration status is irrelevant to the issue of liability, and in proceedings or discovery undertaken to enforce those state laws no inquiry shall be permitted into a person’s immigration status unless the person seeking to make this inquiry has shown by clear and convincing evidence that this inquiry is necessary in order to comply with federal immigration law. (c) The provisions of this section are declaratory of existing law. (d) The provisions of this section are severable. If any provision of this section or its application is held invalid, that invalidity shall not affect other provisions or applications that can be given effect without the invalid provision or application. (e) Any waiver of a provision of this section is contrary to public policy and is void and unenforceable.