California Code, Business and Professions Code - BPC § 22943.4

(a) If an online cannabis marketplace does not verify that a seller of cannabis or cannabis products is licensed as described in paragraph (2) of subdivision (a) of Section 22943.2, the online cannabis marketplace shall, immediately after a consumer has accessed the marketplace, interpose a clear and conspicuous graphic that a consumer must acknowledge and click through before viewing or engaging with the marketplace.  The graphic shall warn the consumer that the marketplace may be displaying, storing, or hosting unlicensed sellers of cannabis or cannabis products.

(b) Any person who identifies an online cannabis marketplace that displays, stores, or hosts an advertisement from, or business information about, an unlicensed seller of cannabis or cannabis products in violation of subdivision (a) may initiate an action to enforce subdivision (a).  A person who prevails in such an action shall be entitled to both of the following:

(c) An online cannabis marketplace that violates an injunction requiring compliance with this section shall be prohibited from operating in California until a receiver appointed by the court issuing the injunction affirms to the court that the marketplace is in compliance.  In any action to enforce an injunction requiring compliance with this section, the party obtaining enforcement shall be entitled to an award of its reasonable attorneys' fees and costs and a civil penalty of up to five hundred thousand dollars ($500,000).

(d) This section shall not be construed as prohibiting a public prosecutor, as described in Section 17204, from bringing an appropriate action to enforce this section.