California Code, Government Code - GOV § 53075.9

(a) Every taxicab transportation service shall include the number of its certificate, license, or permit in every written or oral advertisement of the services it offers.

(b) For purposes of this subdivision, “advertisement” includes, but is not limited to, the issuance of any card, sign, or device to any person, the causing, permitting, or allowing the placement of any sign or marking on or in any building or structure, or in any media form, including newspaper, magazine, radiowave, satellite signal, or any electronic transmission, or in any directory soliciting taxicab transportation services subject to this chapter.

(c) Whenever the local agency, after a hearing, finds that any person or corporation is operating as a taxicab transportation service without a valid certificate, license, or permit or fails to include in any written or oral advertisement the number required by subdivision (a), the local agency may impose a fine of not more than five thousand dollars ($5,000) for each violation.  The local agency may assess the person or corporation an amount sufficient to cover the reasonable expense of investigation incurred by the local agency.  The local agency may assess interest on any fine or assessment imposed, to commence on the day the payment of the fine or assessment becomes delinquent.  All fines, assessments, and interest collected shall be deposited at least once each month in a fund established for the purpose of enforcing this section.

(d) For purposes of this section, “local agency” has the same meaning as specified in subdivision (b) of Section 53075.7.