Cal. Food & Agric. Code § 4191

A city may not impose any tax, except a sales or use tax, on any association that represents more than one county and owns land in each of the counties it represents. A city may not, without the consent of the board of such an association, impose any tax, except a sales or use tax, on any of the concessionaires or rental contractors of the association as to events which take place on the property of the association.