----------------------------------------------------------------- "Le Divorce" by Diane Johnson Dutton, $23.95 -----------------------------------------------------------------

Isabel Walker, the narrator of Diane Johnson's new novel, is a modern version of that traditional literary figure: the American innocent abroad. Yet Isabel's innocence is less sexual than intellectual: She doesn't know what a Trotskyite is, for example. Or, after mentioning her older Parisian lover's prostate, she adds, "whatever that is."

A film-school dropout, Isabel equates life with movies and sprinkles her story with references to Audrey Hepburn, "Gigi," Marlene Dietrich. She even begins the book as if it were a movie, setting up scenes and shots that would play while the credits rolled.

Less forgivable is her narration. Isabel arrives in Paris to help her sister, Roxeanne, through pregnancy just as Roxeanne's adulterous husband bolts. Isabel gets involved with the in-laws, the expatriate community, a wrangle over a painting. But the story keeps spilling out whole chapters before they occur, while subplots involving burglary are left in the shadows. Imagined scenes written in third person smack of earlier drafts, before Isabel became the narrator - making me doubt Diane Johnson as much as Isabel Walker.

"Le Divorce" has some nicely rendered moments, particularly at the in-law's chateau. But the book never thrills; it never touched me emotionally or intellectually. In the end, like a trip to a bad city, I was glad to leave.