Cal. Const., art. XIII, § 29

(a) The Legislature may authorize counties, cities and counties, and cities to enter into contracts to apportion between them the revenue derived from any sales or use tax imposed by them that is collected for them by the State. Before the contract becomes operative, it shall be authorized by a majority of those voting on the question in each jurisdiction at a general or direct primary election.

(b) Notwithstanding subdivision (a), on and after the operative date of this subdivision, counties, cities and counties, and cities may enter into contracts to apportion between them the revenue derived from any sales or use tax imposed by them pursuant to the Bradley-Burns Uniform Local Sales and Use Tax Law, or any successor provisions, that is collected for them by the State, if the ordinance or resolution proposing each contract is approved by a two-thirds vote of the governing body of each jurisdiction that is a party to the contract.