Le Mariage by Diane Johnson

Anne-Sophie is a young French-woman engaged to Tim Nolinger, a struggling American journalist who is hot on the trail of a breaking story: the theft of a valuable illuminated manuscript from a private collection in New York. Rumor has it that the manuscript may be in the hands of Serge Cray, a reclusive film director living outside Paris. As Tim, Anne-Sophie, a pair of American antique dealers, and one amorous member of the local gentry converge on the Cray home, Clara Holly, Cray's Oregon-born wife and a former actress, is propelled into a Kafkaesque nightmare: she stands accused of desecrating a national monument. Add to that a disappearing American; a wrongful arrest; murder; and various suspicions, seductions, domestic crises, and declarations of love, and you have this sexy, stylish delight of a novel.