Need help finding an older WW2 Era movie

In the 1980s, I was required to watch a movie for my American heritage class at BYU. It was an older WW II/Holocaust movie about a man who had to pretend to sympathize with Hitler. As a result he lost a lot of friends but his best friend knew that he was being forced to do this. His best friend wrote him a letter saying that he believed in him, which the man burned in a fireplace.A woman he loved was executed by a firing squad. There was one scene where the man discovered that one of the bulbs in the chandelier of his hotel room was a listening device that the Nazis had planted. Thank you!