It appears to be even more restrictive then that: https://leginfo.legislature.ca.gov/faces/codes_displaySectio...

> An employer shall not rely on the salary history information of an applicant for employment as a factor in determining whether to offer employment to an applicant or what salary to offer an applicant.

That being said, how do you enforce a provision like that in the face of every company having all information on every candidate, seeing that mind reading hasn't been invented yet.