Cal. RTC § 6275

(a) Every person making any retail sale of a mobilehome or commercial coach required to be registered annually under the Health and Safety Code, or of a vehicle required to be registered under the Vehicle Code or subject to identification under Division 16.5 (commencing with Section 38000) of the Vehicle Code, or a vehicle that qualifies under the permanent trailer identification plate program pursuant to subdivision (a) of Section 5014.1 of the Vehicle Code, or of a vessel or an aircraft as defined in this article, is a retailer for the purposes of this part of the vehicle, vessel, or aircraft, regardless of whether he or she is a retailer by reason of other provisions of this part, unless another person is the retailer, as provided in subdivision (b).

(b) Every person, licensed or certificated under the Health and Safety Code or the Vehicle Code as a dealer, is the retailer of a mobilehome or commercial coach required to be registered annually under the Health and Safety Code or of a vehicle required to be registered under the Vehicle Code or subject to identification under Division 16.5 (commencing with Section 38000) of the Vehicle Code or a vehicle that qualifies under the permanent trailer identification plate program pursuant to subdivision (a) of Section 5014.1 of the Vehicle Code, when a retail sale of the vehicle is made through him or her and that person provides to the Department of Housing and Community Development or the Department of Motor Vehicles a notice of transfer with respect to the vehicle pursuant to Section 18080.5 of the Health and Safety Code or Section 5901 or Section 38200 of the Vehicle Code. That person shall hold a seller’s permit and remit tax to the board with respect to those sales in the same manner as a dealer licensed or certificated under the Vehicle Code and making sales on his or her own account. For purposes of this subdivision, “sale” does not include a lease.