Suave, confidential, a bit thicker around the middle perhaps, but otherwise radiating an astonishing amount of boyishness for a man who's 60, French singer Yves Montand gave the first of two performances of his one-man show in the Kennedy Center Concert Hall last night. He's been away from the music hall too long not to welcome him back with warmth. And he's singing too well not to savor the mellowness of his voice and the precision of his art.

But the Concert Hall is such an inhospitable locale for his talents that one can't help wishing the whole affair were taking place elsewhere. Montand is not exactly a miniaturist, but he works subtly and his charm creeps up on an audience, as Sandburg once said of fog, on little cat feet. Montand deals in poetry, but there is nothing obvious about the poetry he purveys. He pursues it in unexpected locales, searches for it in unlikely people, and with patience and an eagle's eye, waits for it to materialize out of seemingly banal situations. If he is allowed to establish the proper note of intimacy, all it takes is a sudden flick of his wrist or a twinkle of his eyes: The poetry is there.

Only it isn't there as often as you might hope at the Concert Hall. Last night an imbalance in the sound system gave every advantage to the eight-piece combo and precious little to Montand himself. But even when the musicians retreated to a reasonably supportive role, Montand was still left facing all that space -- a great white box of it, three stories high. Professional that he is, he never looked lost. But he often seemed out of place.

Without intermission, he delivers nearly 30 songs, leaving the stage only for a brief, but amusing, film clip that shows him dictating a telegram of love to the French equivalent of Lily Tomlin's telephone operator (actually, Montand's wife, Simone Signoret). All but one of the numbers are in French, and a fair share are the standards ("Feuilles Mortes," "A Paris," "Luna Park" and "Le Carrosse") that have been in his repertory for years. Nostalgia may now account for some of their appeal. But only some. Montand sings them with transcendent freshness and the sort of well-honed gestures that defy distance.

Some of his songs, however, are exact little character sketches ("Battling Joe," "Sir Godfrey") and depend for their effectiveness on the very nuances of expression that the Concert Hall swallows up as easily as a whale devours minnows. "Les Bijoux" (the sensual poetry of Baudelaire set to music by Le'o Ferre') and the tantalizing "Sanguine Joli Fruit" are perfect songs for a seraglio, not a marble barn. And when he turns, as he does periodically, to his protest numbers ("Casse-Te tes," "Mon Fre re"), it's as if he's hurling them into a void rather than insinuating them into our consciences.

What works best are the lyrical moments, with the accordian sounding plaintively in the background and Montand waltzing about the stage, eyes half closed, on a cloud of bliss that is utterly contagious. Singing "La Chansonette," he could be 20 all over again, and his rendition of "La Bicyclette" is infused with all the wind-brushed wonder of everyman's springtime.

But there are still those unspoken hostilities between performer and auditorium. They make you wonder how this most ingratiating of singers ever survived his recent week in New York at the Met. In addition to all our cultural centers, maybe it's time to start building a few boites, as well.