Cal. Bus. & Prof. Code § 16604
Every person who, as a condition to a sale or consignment of any magazine, book, or other publication, requires that the purchaser or consignee purchase or receive for sale any other magazine, book, or other publication is guilty of a misdemeanor, punishable by imprisonment in the county jail not exceeding six months, or by fine not exceeding one thousand dollars ($1,000), or by both such imprisonment and such fine.
This section is not intended to prohibit an agreement requiring a person to purchase or accept on consignment a minimum number of copies of a single edition or issue of a magazine or of a particular book or other particular publication.
As used in this section, "person" includes a corporation, partnership, or other association.
This section does not apply with respect to any contract relating exclusively to the sale or consignment of any newspaper of general circulation as defined by Section 6000 of the Government Code.
Ca. Bus. and Prof'l. Code § 16604