The time is 1943 and the scenario the Vieux Port of Marseille. By this time France's Free Zone had been abolished and Nazi occupation had been extended to the whole country. The Vieux Port was a maze of labyrinthine streets and alleys where houses were connected to each other by subterranean passages, hidden openings in the walls and window/roof/window paths. This made the quarter an ideal scenario for the Resistance hiding fugitives, and the plot deals with two British airmen escaped from a POW camp looking for a way to rejoin their force. In 1943 the Nazi occupiers aided by the French police, dynamited much of the historic old town (the movie contains some documentary footage).
There is a subplot involving a character, Dr. Martout, who preys on Jews and other people that need to leave France urgently. Dr. Martout seems to be based on a real character, Dr. Marcel Petiot , a serial killer that operated in Paris during the war and has a movie devoted to his exploits, Docteur Petiot (1990) plus several documentaries. This movie's actual title is Seven Thunders, probably from St. John's Book of Revelation, which doesn't seem to relate to what we see on screen.
After a brilliant career in his native Argentina Hugo Fregonese became a no less successful director in Hollywood. His work began with One Way Street in 1950 and included some biggies such as Blowing Wild (1953), with Gary Cooper and Barbara Stanwyck. He also directed in Europe (the UK in this movie). Fregonese was a solid studio director who could do justice to a good script like in this film, which stands above many other war movies.
