California Code, Revenue and Taxation Code - RTC § 6406

A credit shall be allowed against, but shall not exceed, the taxes imposed on any person by Chapter 3 (commencing with Section 6201) of this part, by any ordinance enacted pursuant to Part 1.5 (commencing with Section 7200), by any ordinance enacted pursuant to Part 1.6 (commencing with Section 7251), and by any ordinance enacted pursuant to Article 2 (commencing with Section 37021) of Part 17 of this division by reason of the storage, use, or other consumption of tangible personal property in this state to the extent that the person has paid a retail sales or use tax, or reimbursement therefor, imposed with respect to that property by any other state, political subdivision thereof, or the District of Columbia prior to the storage, use, or other consumption of that property in this state. The credit shall be apportioned to the taxes against which it is allowed in proportion to the amounts of those taxes.

A credit, otherwise permitted by the foregoing provisions of this section, shall not be allowed against taxes which are measured by periodic payments made under a lease, to the extent that the taxes imposed by any other state, political subdivision thereof, or the District of Columbia were also measured by periodic payments made under a lease for a period prior to the storage, use, or other consumption of the property in this state.