A greaseproof paper is provided for use in food processing and/or packaging of foods in which paper has been rendered oleophobic by treatment with a fluorine-containing polymer. The fluorine-containing polymer may be prepared by polymerizing a fluorine-containing monomer in the presence of a mercapto group-containing organopolysiloxane. The fluorine-containing polymer may be applied to paper by coating onto pre-formed paper, or by applying the polymer as a size during a papermaking process.