In reenacting the rise and fall of the Comedian Harmonists — once one of Europe’s most popular singing groups, silenced by the Nazis in 1934 because three of its six members were Jewish — German filmmaker Joseph Vilsmaier puts another piece of his country’s busted-up jigsaw history back in place. In The Harmonists, the trade-off for the compelling lesson (and welcome musical introduction), though, is a thick topcoat of nostalgia and the presentation of each character as a point on the continuum of Jewish and gentile national identity. Harry Frommermann (Ulrich Noethen), for instance, the imaginative Jewish funnyman who put the group together, announces his lack of religious observance by talking to his dead mother’s headstone. (Lesson: Even secular Jews were persecuted.) Ben Becker, meanwhile, plays the beefy gentile business manager Robert Biberti as a patriot whose love of mother and fatherland kept the troupe in Germany when they might have emigrated to America. And the two men compete for the same lass (Meret Becker), an open-minded woman who is — here’s the lesson — capable of independent-minded decisions in the face of fear.