California Code, Revenue and Taxation Code - RTC § 6047

(a) A marketplace facilitator shall be relieved of the taxes or fees on retail sales facilitated through its marketplace as provided in subdivision (c) if the marketplace facilitator demonstrates to the satisfaction of the department all of the following:

(b) To the extent that a marketplace facilitator is relieved of liability for collection of sales and use tax or any other fee administered pursuant to Part 30 (commencing with Section 55001) under this section, the marketplace seller for whom the marketplace facilitator has facilitated the retail sale is also relieved of liability, unless the marketplace seller is the retailer for those retail sales pursuant to Section 6046. The department may determine the manner in which a marketplace facilitator or marketplace seller shall claim the liability relief provided in this section.

(c) The liability relief provided under this section shall not exceed the following percentage of the sum of all sales and use tax and any other fee administered pursuant to Part 30 (commencing with Section 55001) due on sales facilitated by a marketplace facilitator for marketplace sellers, which sales shall not include sales by the marketplace facilitator or persons related to the marketplace facilitators:

(d) Nothing in this section shall be construed to relieve any person of liability for collecting but failing to remit to the department sales and use tax or any other fee administered pursuant to Part 30 (commencing with Section 55001).