CA Veh Code Section 5202

(a)

A license plate issued by this state or any other jurisdiction within or without the United States shall be attached upon receipt and remain attached during the period of its validity to the vehicle for which it is issued while being operated within this state or during the time the vehicle is being held for sale in this state, or until the time that a vehicle with special or identification plates is no longer entitled to those plates; and a person shall not operate, and an owner shall not knowingly permit to be operated, upon any highway, a vehicle unless the license plate is so attached. A special permit issued in lieu of plates shall be attached and displayed on the vehicle for which the permit was issued during the period of the permit’s validity.

(b)

This section shall become operative on July 1, 2012.