Here are a list of precedents for the case.
Metromedia Inc. v. San Diego (1981): Held an ordinance invalid as a content based regulation because the City treated commercial speech more favorably than noncommercial speech.
Simon & Schuster Inc. v. New York Crime Victims Board (1991): The Court held that if there existed sufficiently compelling interests, then support for a content based restriction could be valid.
Linmark Associates Inc. v. Willingboro (1977): Found an ordinance that prohibited homeowners from placing "For Sale" signs on their property to be unconstitutional because it restricted the free flow of truthful information.
City Council of Los Angeles v. Taxpayers for Vincent (1984): The Court upheld an ordinance that prohibited the posting of signs on public property in order to avoid visual clutter.