California Code, Revenue and Taxation Code - RTC § 7056.5

(a) Except as otherwise provided by this article or other express provision of law, the information furnished or secured pursuant to this part shall be used solely for the purpose of administering the tax laws or other laws administered by the person or agency obtaining it. Any willful unauthorized inspection or unwarranted disclosure or use of the information by the person or agency, or the employees and officers thereof, is a misdemeanor. For purposes of this section, “inspection” means any examination of confidential information furnished or secured pursuant to this part.

(b) The board shall notify a taxpayer of any known incidents of willful unauthorized inspection or unwarranted disclosure or use of the taxpayer's confidential tax records, but only if criminal charges have been filed for the willful unauthorized inspection or unwarranted disclosure.