Cal. Rev. & Tax. Code § 7203.5
The State Board of Equalization shall not administer and shall terminate its contract to administer any sales or use tax ordinance of a city, county, redevelopment agency, or city and county, if such city, county, redevelopment agency, or city and county imposes a sales or use tax in addition to the sales and use taxes imposed under an ordinance conforming to the provisions of Sections 7202 and 7203.
The board shall give such city, county, redevelopment agency, or city and county written notice of termination, stating the reasons therefor and the effective date of the termination, which shall be not earlier than the first day of the first calendar quarter commencing at least 30 days after the mailing of the notice to the city, county, redevelopment agency, or city and county. If the cause for termination is not cured within the time specified in the notice, the board shall not administer the ordinance until the cause for termination is removed and a new contract for the administration of the ordinance executed. Such contract shall be operative not earlier than the first day of the first calendar quarter commencing after its execution. During the period of time that the board is not administering the sales and use tax ordinance of a city, county, redevelopment agency, or city and county, no ordinance of such city, county, redevelopment agency, or city and county shall be considered to be an ordinance enacted in accordance with this part.
Nothing in this section shall be construed as prohibiting the levy or collection by a city, county, redevelopment agency, or city and county of any other substantially different tax authorized by the Constitution of California or by statute or by the charter of any chartered city.
Ca. Rev. and Tax. Code § 7203.5