An assassin and a suicidal schlub check into a hotel—and though what happens next shouldn’t be any more amusing than a groan-inducing joke, A Pain in the Ass is an absolute charmer. The day a mob informant gets escorted from prison to the courthouse, Jean Milan (Richard Berry) moves into a room where he prepares to assassinate the guy. But his next-door neighbor turns out to be Francois Pignon (Patrick Timsit), a photographer sent to cover the event, who instead decides to kill himself after his wife runs off with her psychiatrist. Pignon’s bungled attempt to hang himself from a showerhead results in gushing pipes, a frantic bellhop, and Milan’s involuntarily involvement when he has to agree to look after Pignon to prevent the bellhop from calling the cops. French writer-director Francis Veber has a remarkable gift for light-as-air comedy, wringing laughs out of even small, off-plot moments, including one smug kid’s attempt to steal a candy bar. (The boy quickly loses his cool when the prisoner’s SWAT guards stop at the shop.) And Timsit makes Pignon a wonderful sadsack, a quick-witted lump who irritates people yet manages to elicit their sympathy. The film is the rare farce that never gets tiresome.

Friday at 9:15 p.m. Also at 9:30 p.m. on Saturday, April 18. Both showings at Avalon Theatre.