Cal. CIV § 9402

The direct contractor shall serve on the public entity an affidavit, together with a copy of the affidavit, in compliance with the requirements of Chapter 2 (commencing with Section 8100) of Title 1, that includes all of the following information: (a) An allegation of the grounds for release of the funds and a statement of the facts supporting the allegation. (b) A demand for the release of all or the portion of the funds that are alleged to be withheld improperly or in an excessive amount. (c) A statement of the address of the contractor within the state for the purpose of permitting service by mail on the contractor of any notice or document.