Magdalena Kozena has been a busy Czech mezzo in New York lately. She has appeared at the Met, singing Dorabella in Mozart’s “Cosi fan tutte.” In Carnegie Hall, she has sung Mahler with the Berlin Philharmonic, and Mussorgsky and Lutoslawski with the Philadelphia Orchestra. And, on Sunday night, she sang Rameau and Gluck in Zankel Hall, the downstairs (and sometimes down-market) venue at Carnegie.

As you might guess, Miss Kozena is one of the starrier singers among us, and she deserves that fame. If you want to hear Bach singing, listen to her 1999 album on the Archiv label. If you want to hear Czech songs, listen to her 2000 album with the pianist Graham Johnson on Deutsche Grammophon. Like many singers, this one has had her problems, but when she has it together, she is an example.

On Sunday night, she was the guest star with Les Violons du Roy. This is an early-music group based in Quebec, founded by the conductor Bernard Labadie. Like his group, Mr. Labadie is a Quebecker, and he conducted on Sunday night. The program was devoted to the French Baroque: to the aforementioned composers, Rameau and Gluck, with one rebel thrown in. Or rather, Rebel: Jean-Fery Rebel, whose “choreographic symphony,” “Les Elemens,” the little orchestra played.

I must tell you, right off the bat, that Miss Kozena looked stunning – model-thin, but stunning. (“But?”) We might ask the question, How many singers have foundered on the shoals of major weight loss? But Miss Kozena will not founder, if she keeps her wits about her.

At Zankel Hall, she sang arias from three Rameau operas and three Gluck operas. One of the latter was “Alceste,” a surprise hit of the Salzburg Festival last summer. It should be a hit all over, really. If people know anything from “Alceste,” it tends to be Maria Callas’s recording of “Divinites du Styx.”

Magdalena Kozena displayed her considerable gifts: technical control, interesting sounds, musical and dramatic understanding. Intonation was no problem, soft singing seemed a breeze. The lower register was solid, the upper register easy. She does not give you one color, this singer. For example, in an aria from “Alceste,” she bleached all the vibrato out of a pivotal E – very effective (and eerily effective).

Typically, Miss Kozena laid on plenty of operatic emotion, but did not let this emotion warp the musical line. She was musician first, actress – or character – second. Or perhaps she prefers to think of herself as a unified performing being. (Try not to get into an opera star’s head.) She was sensitive to each note, each syllable, the dramatic situation. Her recitatives were attacked well, or caressed well, depending. And she seemed to relish the French language, for which she has an affinity.

One of the Gluck arias was “Dieux puissants que j’atteste … Ma fille, je la vois … Jupiter, lance la foudre,” from “Iphigenie en Aulide.” (Got all that?) It is not quite a mad scene, but there’s madness in it, or at least furious desperation. Miss Kozena conveyed the essence strikingly. She was unhinged – and yet hinged, technically, musically. Really, this was singing of a very high order.

The orchestra – Les Violons du Roy – was not so bad itself. This humble little group is well-drilled – better drilled than many a mighty orchestra one hears on our stages. They opened the concert with a suite from Rameau’s opera “Dardanus,” in which the players were both graceful and lively. They showed vigor, but not vulgarity. The strings had a “period” grittiness – but were not overly coarse. In some dances, the orchestra was almost primal, but they were never far from courtly elegance. This is an achievement.

One of Rameau’s tambourine dances almost made you want to get up and cut a rug. (I said almost.)

And if you play one suite from “Dardanus,” why not another? One of the movements of this second suite promises the “bruit de guerre,” the noise of war – and, believe it or not, that’s exactly what we got (with some help from a bass drum). The orchestra was positively thrilling, and they proved themselves more than a backup band for a marquee singer.

We all have our lists of underrated composers, to go with our lists of overrated composers. Rameau has long been on my underrated list. So I especially appreciated hearing him, along with his confreres. The French Baroque in general is underperformed, despite the efforts of William Christie and Les Arts Florissants (and those of these Quebeckers). Even so, a concert consisting of the French Baroque alone … is a concert with a lot of French Baroque on it. Good thing the music-making was first-class.