Cal. Bus. & Prof. Code § 18450

It is a misdemeanor, in connection with the sale of a motor vehicle by a person engaged in the business of selling motor vehicles at retail, for such person to accept assignment of an insurance policy, or rights thereunder, pertaining to any motor vehicle traded in by the purchaser, unless all amounts realized on such policy or rights by such person be credited by the dealer to the buyer on the next monthly payment due or same shall be refunded to the buyer.