Walking away from Theatre Châtelet this afternoon, I felt as though my relationship with France and its notoriously perplexing people and culture had at long last reached some degree of depth. Three weeks into my four-month stint studying at L’Institut d’études politiques de Paris for my Masters in International Affairs, I seem to have found the heart beating within this city besieged by tourists and high prices.

And all it took was a packed audience, and 90 minutes with Michel Legrand and his plaintive score for the film, Les Parapluies de Cherbourg (The Umbrellas of Cherbourg). Theatre Châtelet offered a mere four performances of this devastatingly gorgeous concert staging of Parapluies, featuring another French institution, the opera star Natalie Dessay as Geneviève’s devoted mother.

Set in Cherbourg, Normandy in the 1950s, Parapluies focuses on an ill-fated love affair between 16-year-old Geneviève (Marie Oppert, 17, in a breakthrough performance) and Guy, a dashing young auto mechanic. Shortly after they fall head over heels, Guy is drafted to the French army to fight in Algeria, and Geneviève sings the unforgettable “Mon amour, je t’attendrai toute ma vie,” a melody that transforms into a leitmotif that never quite resolves itself.

While Guy is at war, Geneviève discovers she is pregnant with his daughter yet then agrees to marry Roland Cassard, a Parisian jeweller (silk-voiced baritone Laurent Naouri). Guy returns home limping and battered from war, struggling to resume normal life while trying to cope with Genevieve’s departure.

This is not a tragic film, however, and Guy too ends up happily married, eventually comfortable enough with his situation that when he and Geneviève encounter one another in Cherbourg, Guy opts against meeting their daughter and the film ends with Guy greeting his wife and playing with his son in the snow.

Filled from beginning to end with continuous verismo-like underscoring and sung recitativo, Parapluies is operatic in its structure yet Legrand’s atmospheric music approaches a degree of subtlety—which Massenet and Weill alike would envy—that places it in a genre of its own. Just when the score almost reaches the point of gaudiness, Legrand switches into an entirely different mode, ranging from subtle pizzicato to big-band. Under the composer’s lithe baton, the music never swells to melodramatic proportions and that seems to be precisely what he intends.

Ms. Dessay, who has had a triumphant but often turbulent career as a coloratura soprano, was my reason for seeing this performance. (She also recently recorded some of Legrand’s beloved tunes in a new album. But what I will remember most is the Paris audience’s unparalleled show of love and appreciation for Mr. Legrand. Now 82, the three-time Oscar winner is a bona fide legend here in France, and this was truly his show.

As conductor he had a remarkable palette with which to work—the nearly 80 musicians of the Orchestre national d’Île-de-France, who deftly handle the delicate score and are impressive in the few but memorable jazz-infused outbursts allowed by Legrand. To top it off the maestro gets to make a grand entrance in a dark raincoat as the ensemble shuffles around him carrying umbrellas.

Once Marie meets Guy, the sheltered teen finds herself in a fast train experiencing the greatest pleasures and travails of life. Oppert confidently guides the audience through Marie’s journey and she sings with clarity, poignancy, and maturity. As Guy, tenor Vincent Niclo is suitably appealing both vocally and dramatically, though the libretto offers little opportunity for the audience to connect with, or comprehend the strength of, his love for Marie.

This is a significant event in Dessay’s career as it is among her first appearances outside of the purely operatic realm where she earned her reputation as a fearless exponent of the Queen of the Night and other stratospheric roles. Dessay has long stated that she views herself primarily as an actress—and this has caused some rumblings among opera purists. She is without question an inspired choice for the role of Madame Emery, never fully camouflaging her own vulnerability while consoling Marie as she experiences love for the first time. Much of the role lies in Dessay’s lower range, which can often lack tonal richness, though arguably the frailty of tone suits the character well.

Yet while the cast and orchestra deserve great credit, the presence of Legrand on the podium elevates this rather sparse production to the level of a major artistic milestone. Over the past three weeks, I have sought to acquaint myself with Paris and while the city is constantly overwhelming, I had yet to reach, and I had been longing to reach, its emotional core. These 90 minutes with Les Parapluies de Cherbourg allowed me a brief window into something resembling collective euphoria here in the City of Light. “Je s’attendrai toute ma vie…”