California Code, Vehicle Code - VEH § 285

(a) For commission, money, or other thing of value, sells, exchanges, buys, or offers for sale, negotiates or attempts to negotiate, a sale or exchange of an interest in, a vehicle subject to registration, a motorcycle, snowmobile, or all-terrain vehicle subject to identification under this code, or a trailer subject to identification pursuant to Section 5014.1, or induces or attempts to induce any person to buy or exchange an interest in a vehicle and, who receives or expects to receive a commission, money, brokerage fees, profit, or any other thing of value, from either the seller or purchaser of the vehicle.

(b) Is engaged wholly or in part in the business of selling vehicles or buying or taking in trade, vehicles for the purpose of resale, selling, or offering for sale, or consigned to be sold, or otherwise dealing in vehicles, whether or not the vehicles are owned by the person.