Philippe Garrel’s latest is a look back, by someone who was there, at the idealism of May ’68, and for those still stunned by the ineptitude of Bernardo Bertolucci’s attempt to do the same in The Dreamers, its tonic effect comes not a moment too soon. William Lubtchansky’s crisp black-and-white cinematography renders textures of stone and faces with an austere, classical power that gives gravity to Garrel’s scenario of politics, love, and hashish. And the film isn’t just a kind of reconstitution; it’s also the record of a present-time struggle — not only by the actors, who include the director’s son, Louis Garrel, but also by the very apartments and vacated Paris streets where the story is set — to exist for themselves rather than being just the dream, or even the dialectic, of an aging director looking at his past.