Transit is based on a 1944 novel by Anna Seghers, in turn based on her experiences as a German Jewish Communist political refugee in Marseilles trying to get out of Vichy France to Mexico. The protagonist is a German illegally in France, who travels from Paris to Marseilles, through chance assumes the identity of a dead German leftist writer who has an exit visa to Mexico, and finds himself involved with both the writer's estranged wife and the wife and son of a fellow German illegal.
What made the movie work for me is that it is not a routine World War II vintage costume drama. Director-Writer Christian Petzold has chosen to set the entire story in present day France. There are no Nazis, no swastikas, and no political explanations. There are only the omnipresent French police checking papers in the street, raiding hotels and apartments, and rounding up illegal aliens for deportation to an unnamed destination, assisted by good French citizens either venal or patriotic, and the desperate struggle of the refugees to procure legitimate identity and travel documents in the face of bureaucratic indifference or hostility. It all feels like it could be happening six months from now, there or, for that matter, here. The contemporary setting greatly increases the tension by taking away historical cues -- you have no idea how it is going to come out or whether the hero will make his getaway to Mexico.