“Avenue Montaigne” is the sort of popular French fare that makes American movie reviewers sound hungry: “light as a profiterole,” or perhaps a “soufflé” (which hopefully does not collapse from the story’s delightful “breeziness”). For this effortlessly smooth trifle directed by 30-year screenwriting veteran Danièle Thompson, junk food snacks are the more apt comparison. It’s reliable enough for a short-term pick-me-up, but afterward you feel as if you’ve had nothing at all.

The opening montages of Paris and the conservative chic of Avenue Montaigne (like Fifth Avenue but with a theater) herald our charming tour through an urbane ensemble of life crises. A famous pianist, Jean-François (Albert Dupontel), tires of the artifice and grind of his innumerable concert performances. A hyperneurotic actress, Catherine (Valérie Lemercier), earns big bucks on a TV drama but longs for a serious movie role, and meanwhile dithers in a traditional stage comedy. And, filling the slot of shadow-casting patriarch, Jacques (Claude Brasseur), an ailing old millionaire, prepares to auction off his monumental collection of art, to the disappointment of his grown, grown-distant son Fred (Christopher Thompson, the director’s son).

Ms. Thompson is too practiced a scribe not to dress up her goods a little, so she helpfully provides a fresh-faced guide in young Jessica (Cécile de France, the ever rising star last seen here in “High Tension” and “Russian Dolls”). More an explorer than guide, really: The coltish country girl is a newcomer to the big city, working as the lone waitress among waiters in an old-fashioned brasserie on the avenue. On her rounds to the neighboring hotel and theater, this blithe spirit is quickly adopted by the natives as she falls into one conversation after another while serving or delivering drinks or food. Her genial curiosity either gives touristic accompaniment, or, viewed more functionally, helps remind us to be interested in the mix-and-match cosmopolites.

This might be why “Avenue Montaigne” feels like a trip to Paris with someone who introduces you to all her friends to allow fleeting dips into their dramas. Characters are enclosed in the self-explaining nostalgia to denizens of a particular social circle. The pianist is married to his manager (Laura Morante), but everyone knows it can’t last if he starts to chafe at the routine. And have you heard about Grumberg pere taking up with the young ex-girlfriend of Grumberg fils? It will be so difficult for them to reconcile, but they must, you know.

Some relief comes courtesy of Ms. Lemercier as the frantic, impatient actress, Catherine. Her urge to cut through nonsense in pursuit of a vaunted ideal of artistic authenticity produces a frazzled, barbed expression from Ms. Lemercier that gooses the film whenever she appears. As she tries to get the attention of a respected American director (played by the American filmmaker Sydney Pollack) at the brasserie, and later presses her ideas for his movie about Simone de Beauvoir, it’s a welcome blast of personality with a nimble wit about the sort of characters who make their own problems (a quality sorely lacking elsewhere in the film).

Besides Ms. Lemercier’s outbursts, Ms. de France’s tender visits with her grandmother (Suzanne Flon) near the beginning and end of the movie are also a refreshing change from the various reconciliations and self-emancipations. The sweet-tempered grand dame recounts her own times as a wide-eyed young woman in the bustling capital, tinged with the clarity of a former factory worker. (“Avenue Montaigne” is dedicated to Ms. Flon, who died shortly after filming at 87.)

The fleetly edited film swoops and glides through its entanglements and impasses, with Jessica on hand to hear the pianist’s lament for vanishing listeners intimidated by classical music, or to eavesdrop on the younger Grumberg’s fruitless assignation with his ex. Moments that are not, well, breezy are glazed with a wistfulness for art and time’s passing that inoculates against self-seriousness. One supporting role, a theater concierge about to retire (Dani, a singer but still best known to me for “Day for Night,” François Truffaut’s valentine to cinema), appears to exist just for another dose of rose-tinted retrospection.

“Avenue Montaigne” could use some of the insight and meaningful sense of complication in “Look at Me,” a film in a similar vein by another screenwriter-director, Agnès Jaoui, and perhaps also a suitable title for this film’s self-regarding smart set. Ms. Thompson instead gratuitously orchestrates a climactic redemptive roundelay between the pianist’s concert performance, the Grumberg art auction, and Catherine’s stage performance. And, outdoing even a critic’s belabored food metaphors, the movie resolves neatly and ends like a meal — or a travel show: with our hero and her new beau tucking into dessert by the nighttime glow of the City of Light.