The current Calif Motorcycle Rider's Handbook, page 3, states that:
"If you operate a motorized bicycle which meets the definition of VC §406[b], you: • Must be 16 years of age or older. • Must wear a properly fitted and fastened bicycle helmet. • Are exempt from the motor vehicle financial responsibility, driver license, and moped plate requirements. (VC §12804.9"
This seems to contradict a previous post by Jim stating that a Class C license is required. When I first read the Vehicle Code requirements, it seemed a Class C was required, but I hope/plan to ride a moped without one, carrying a copy of the Rider's Handbook in case of trouble.