Could someone please help me with the title of an old B/W movie I saw as a child about an undercover american Secret Service agent infiltrating the german army during world war 2(I think)? I remember the movie being very dark and intense. I recall a scene where the american is in a restaurant having a meal and he forgets to use his knife and fork, only using his fork as americans do, thus
putting his life in danger. I would appreciate any information, thanks