CAL. BPC CODE § 7034 : California Code - Section 7034

(a) No contractor that is required to be licensed under this chapter shall insert in any contract, or be a party, with a subcontractor that is licensed under this chapter to any contract which contains a provision, clause, covenant, or agreement which is void or unenforceable under Section 2782 of the Civil Code.

(b) No contractor that is required to be licensed under this chapter shall require a waiver of lien rights from any subcontractor, employee, or supplier in violation of Section 8122 of the Civil Code.