Frederick Wiseman’s magnificent documentary offers a portrait of suppleness and agility—not just of the dancers’ bodies but of the august institution of the title. Like all his documentaries, La Danse forgoes voiceover and identifying intertitles, allowing spectators’ full immersion into the action within the walls of the Palais Garnier, the 19th-century neo-Baroque opera house where the company rehearses and performs—while also demanding that we pay closer attention, with none of nonfiction film’s usual cues to guide us. Roughly two-thirds of La Danse is devoted to rehearsal and performance, shot in deeply satisfying long takes of gorgeous young men and women starting, stopping, listening, questioning, repeating, perfecting. The rest is behind the scenes, and as Wiseman shows empty corridors, the cafeteria, sewing rooms, and the nightly cleanup of the 2,200-seat theater, the stealth star of La Danse emerges: Brigitte Lefèvre, the company’s composed, elegant artistic director. Shown in a meeting discussing the finer distinctions between “benefactors” and “big benefactors,” Lefèvre nimbly tackles the potential messiness—but absolute necessity—of crass commerce fueling high art. When not administrating, Lefèvre seems happiest as a maternal martinet, reminding one new student, “To do is the most important.”