Cal. Bus. & Prof. Code § 21652

Every junk dealer or secondhand dealer shall, before accepting for resale from any person any finished product, new item of finished or merchandisable quality, inventory item of new materials or finished quality, or other goods and materials in such a state or condition as to show that they are neither abandoned nor scrapped, shall require that such person present adequate evidence of authority to sell. Violation of this section is a misdemeanor.