California Code, Family Code - FAM § 3102

a. A physician licensed pursuant to the provisions of Title 45 of the Revised Statutes who provides medical services to a beneficiary of the Medicare program established pursuant to section 1801 of the federal Social Security Act (42 U.S.C. § 1395 et seq.)   1 shall prominently display in his office, and include on all billing statements to Medicare beneficiaries, his policy regarding the imposition of any charge in excess of the limiting fee for a service as determined by the United States Secretary of Health and Human Services.

b. The physician shall prominently display in his office, and inform, in writing, the State Board of Medical Examiners, of any changes in his excess charge policy before the imposition of these changes in accordance with federal regulations.