CA Veh Code Section 11615.5

It is unlawful and a violation of this code for a person holding a license under this chapter to make a retail sale of a motor vehicle, except to the lessee of such vehicle, required to be registered pursuant to Division 3 (commencing with Section 4000) or subject to identification pursuant to Division 16.5 (commencing with Section 38000) if such person files with the department a report of sale as provided in Section 4456 with respect to such retail sale, without making the return and payment of any sales tax due and required by Section 6451 of the Revenue and Taxation Code.