Cal. Rev. & Tax. Code § 461

Every person who willfully states anything which he knows to be false in any oral or written statement, not under oath, required or authorized to be made as the basis of imposing any tax or assessment, is guilty of a misdemeanor and upon conviction thereof may be punished by imprisonment in the county jail for a period not exceeding six months or by a fine not exceeding one thousand dollars ($1,000), or by both.