During the fake interrogation of Eddie Chapman in London, he is asked what film he saw in the movie theater. He answers; "Warsaw Concerto" with Anton Walbrook and Sally Gray." This could be an inside joke and reference to the film Suicide Squadron (1941) with participation of the mentioned actors and written by this film's director Terence Young.
Director Terrence Young also directed Bond films Thunderball with Claudine Auger (Paulette) and Dr. No with Anthony Dawson (Major Stillman). Another Bond tie-in is Gert Frobe (Colonel Steinhager) who previously starred as Goldfinger.
The trivia items below may give away important plot points.
While the movie ending implies that Baron Von Grunen (Yul Brynner) dies after being shot in the back (or allows the viewer to infer such), actually Chapman and Von Grunen remained friends after the war. Von Grunen even attended the wedding of Chapman's daughter.