Cal. Civ. Proc. Code § 1582
(a)
(1) An agreement to locate, deliver, recover, or assist in the recovery of property reported under Section 1530 is invalid if either of the following apply:
(2) An agreement to locate, deliver, recover, or assist in the recovery of property reported under Section 1530 made after payment or delivery under Section 1532 is valid if it meets all of the following requirements: