French decorating can be sparse or lushly layered, but it is always attractive.French furniture spans many styles and periods. Even modern chic French interiors often include pieces from a number of periods, including Baroque, Regency, Rococo and Empire---perhaps even with a bit of Art Nouveau and Art Deco tossed in the mix. Collect antiques, or good reproductions, in historical French styles. Mix them all together, as if you inherited several centuries' worth of family pieces. Don't be…