Forty years ago, in his ravishing breakthrough movie "Before the Revolution," Bernardo Bertolucci created a hero torn between his desire to be a revolutionary and his sensuality. The same feverish ambivalence underscores "The Dreamers," his eroticized ode to the youthful passions of Paris in 1968. The three protagonists--the American student Matthew (Michael Pitt) and the inseparable, highly theatrical French twins Theo (Louis Garrel) and Isabelle (Eva Green)--are swept up in the revolutionary fever that would lead to riots across the country, but their deepest passion is reserved for movies. Cinephiles to the bone, they fight over the relative merits of Keaton versus Chaplin, act out scenes from "Queen Christina," run full tilt through the Louvre exactly like the trio in Godard's "Band of Outsiders."

While the twins' parents are off in the country, they invite Matthew to live in their Paris apartment. Shut off from the world outside, they engage in a mutual seduction. They shed clothes and inhibitions; like hothouse flowers, they blossom in artificial light, their erotic fantasies nourished by all the movies they've seen, the line between real and reel life indistinguishable.

Bertolucci, as movie-mad as his characters, fills "The Dreamers" with old film clips ("Top Hat," "City Lights," "Shock Corridor," "Breathless," "Mouchette," etc.) and uses nostalgia-inducing snippets from the scores of "The 400 Blows" and "Pierrot le Fou" and other New Wave classics, alongside Jimi Hendrix and Janis Joplin. The film, in fact, is written by a film critic, Gilbert Adair, based on his novel "The Holy Innocents." Adair also wrote "Love and Death on Long Island," and his obsessions perfectly mesh with Bertolucci's. Did he have "Les Enfants Terribles" in the back of his mind when he dreamed up the exhibitionistic, incestuously close Theo and Isabelle?

Bertolucci sees the danger in his characters' solipsism, but he adores their adventurousness, their passion--not to mention their unblemished flesh. Unapologetically graphic (though mild compared with such French movies as "Baise Moi"), this is not a movie for those upset by a glimpse of a Jackson breast; Fox Searchlight, wisely recognizing how integral its eroticism is, is releasing it with an NC-17 rating. Bertolucci has always been one of the great cinematic sensualists, and "The Dreamers" is a must-see for anyone who's ever worshiped at the altar of cinema. But it's not on the same level as Bertolucci's "The Conformist," or even his "Last Tango in Paris," which it inevitably evokes. The tale is a bit too insular and claustrophobic for its own good: in the end these characters lack the depth and complexity to resonate deeply. The pleasures of "The Dreamers" stay mostly on the surface. But when the surface is as stylish and sexy as this, it's hard to complain.