One of the titles this movie played under is AT DAWN WE DIE; confusingly, another is TOMORROW WE LIVE. It's directed by George King, who made his mark with cheap quota quickies in the 1930s, most notably the Tod Slaughter melodramas; it stars John Clements, the distinguished stage actor-manager, whose best-known movie role was as Harry Faversham in the great 1939 THE FOUR FEATHERS. That was British film making in the War, when the cinematic world turned upside down, and this story of how Clements wandered into town and found himself in the middle of underground operations and sabotage that was invariably forewarned with the Cross of Lorraine (the symbol of the Free French), drives everyone crazy.
It's certainly not a subtle movie on any terms; the mystery, of who was actually in charge of the Resistance in town and who were the collaborators were easy to figure out, simply by assuming this would hit every stereotype of the genre. Yet I found it carried out with such easy confidence in its competent cast, that it rolled right along, as easily as any American movie of the period. If you're in the mood for one of those movies with evil Nazis, freedom-loving Frenchmen who face a firing squad singing "Le Marseillaise" and the inevitable triumph of good over evil, this should fit the bill.