The 44-year-old french director Olivier Assayas, best known for Irma Vep, offers up his own variation on the vagaries of companionship and amour and mortality in Late August, Early September (at the Film Forum), a mellifluous contemporary roundelay about Parisian friends in their thirties. It has some of the same resonance as Claude Sautet’s 1974 Vincent, François, Paul and the Others, but it’s about a somewhat younger and scroungier crowd. The cast, including Virginie Ledoyen, François Cluzet, and Mathieu Amalric, is as well coordinated as a fine chamber-music ensemble; their entrances and vanishings and re-entries play like recurring motifs.