California Code, Penal Code - PEN § 4852.21

(a) A person to whom this chapter applies shall, prior to discharge or release on parole or postrelease community supervision from a state prison or other state penal institution or agency, or prior to discharge or release on mandatory supervision from a county jail, be informed in writing by the official in charge of the place of confinement of the person's right to petition for, and of the procedure for filing the petition for and obtaining, a certificate of rehabilitation and pardon pursuant to this chapter.

(b) Prior to dismissal of the accusatory pleading pursuant to Section 1203.4, the defendant shall be informed in writing by the clerk of the court dismissing the accusatory pleading of the defendant's right, if any, to petition for, and of the procedure for filing a petition for and obtaining, a certificate of rehabilitation and pardon pursuant to this chapter.