The letter was sent to Central Casting of Burbank, the largest background casting business in the entertainment industry.
The letter advises casting companies of the details of State Labor Code section 1702.1 that prohibits requiring fees for registration, photo processing and other services, or for applying for a job.
"An employer that requires a mandatory fee from actors applying for work as background performers in the entertainment industry violates this important rule," said California Labor Commissioner Julie Su.
L.A. City Attorney Carmen Trutanich's office concluded an investigation that determined Central Casting was requiring a "photographic/electronic image fee" of $25 in exchange for assistance finding work in film, TV, music videos and print.
The agencies were warned of misdemeanor prosecution of up to a year in jail and a fine of $10,000.