Cal. Mil. & Vet. Code § 616

Any person who displays a red flag, banner, or badge or any flag, badge, banner, or device of any color or form whatever in any public place or in any meeting place or public assembly, or from or on any house, building, or window as a sign, symbol, or emblem of forceful or violent opposition to organized government or as an invitation or stimulus to anarchistic action or as aid to propaganda that advocates by force or violence the overthrow of government is guilty of a felony.