The French long have been known for their preoccupation with matters of the heart. When Franc,oise Sagan appeared on the scene, publishing her first novel, "Bonjour Tristesse," in 1954 at the age of 18, her precocious mastery of the topic quickly made her a national heroine. For, despite being identified in a witty and wide-ranging contemporary study ("Love and the French" by Nina Epton, 1959) as "a notorious representative of the younger generation," Sagan, like her elders, believed, underneath the fashionable ennui of her characters, that love's what makes the world go 'round. (In fact, Epton reported, according to the French Institute of Public Opinion, only 5 percent of French youth interviewed then in a poll felt that love isn't the most important thing in life. What a country!)

Having no current statistics on France, however, I can't quite update those 1959 figures; Sagan, though, hasn't changed. Her latest book, "The Painted Lady," is a sort of--excuse the French--bateau d'amour, a "Love Boat" gone Gallic. Has Sagan been watching American television, or is it simply that the sturdiness of the formula--shipboard romances and transformations--was irresistible? Here, a 10-day Mediterranean cruise for rich music lovers aboard the S.S. Narcissus (not too subtle, that) provides the setting, and though we're told that "people fought for cabins two years in advance," we actually meet very few of these passengers. Eight in all, plus two of the performers and two crew members, unless you count "an elderly American, a flat-footed robot," who's allowed to take one of the featured players for a fleeting turn on the dance floor.

Of course, 12 characters are all anyone needs--more than sufficient, really--to float a plot. But even for a story that takes place in a closed milieu "The Painted Lady" is a singularly airless work, more stagy than novelistic. Sagan works hard to keep the thing from sinking--it is, after all, probably twice as long as any of her earlier books--but still it seems to have more promise as a sitcom than as printed fiction. Or as a staple of provincial rep melodrama it also might make better sense: Each time one of the characters disappears, the reader practically can feel him step into the wings, perhaps to smoke a cigarette or change costume while awaiting the next cue. These are roles, not human beings.

In her novels, Sagan's characters often are journalists or theatrical people. She prefers, too, to write about folk who are comfortably well-off, frequently rich. There's no second class on the Narcissus, while the first might as well not exist; our attention is on the deluxe deck. Clarisse, a 32-year-old heiress, alcoholic and given to hiding herself behind garish makeup, is the "painted lady" of the title (although there's nothing stopping it from also being a metaphor for love's many guises). Her husband Eric, a left-wing newspaper publisher whose delusions of personal grandeur don't square with his professed political sentiments, unfathomably despises his wife, taking pleasure in her state of perpetual self-degradation.

The remaining passengers we are allowed to meet all watch this unhappy couple with varying degrees of interest and perception. Both Edma, the aging but still elegant wife of a nondescript magnate, and la Doriacci, "the diva of divas," engaged to sing on board, are worldly enough to understand that Eric is a vain and morally trivial fellow, and a cheap sadist, to boot. Olga, on the other hand, an opportunistic starlet who's latched onto Simon, a film producer new to the limelight who sees the cruise as a doorway to "culture," views Eric with predatory desire. Simon himself first pities Clarisse, then is capitivated by the gentle, insecure woman beneath the "sad clown" paint.

The characters, in typical shipboard fashion, spend most of their time, as the days pass, in continual observation of each other. Shifting alliances take up the rest of it. Sagan, meanwhile, the actual cruise director, occupies herself with meandering, if occasionally acute, exposition about the personal peculiarities of the assemblage. She likes the simple paradoxes of temperament: the radical who's in reality a reactionary snob, the gigolo who's willing to sacrifice all to love, the ravaged-seeming singer whose freshness at the games of love gives girlish allure to her legendary sexual appetites.

As the title implies, artifice plays a large part in the events, as the Narcissus steams from port to port. None of these people will be exactly the same when stepping off the boat as when mounting the gangplank; their pretensions and disguises are stripped away. Love redeems two of them, destroys another. Is it the fault of the thick and stilted-sounding translation that one feels physical relief when the docking of the Narcissus at Cannes takes place, thus ending the action? It may not, after all, be either boredom or mal de mer that causes our unease with Sagan's stereotypes and caricatures--who indeed could be the staples of a tempting chocolate box of a novel--but the use of such outmoded words as "corker" and "mug" for idiomatic English. This is artifice twice over.

When the last cabin has emptied, it's not so much the "Love Boat" that "The Painted Lady" reminds me of; it's more like the "love bloat." Or maybe Arnold Schwarzenegger: the familiar ingredients of the ordinary Franc,oise Sagan novel are here, slender and sensitive, but they went and pumped iron.