During World War II, Mel Brooks served as a Corporal in the U.S. Army in France, where part of his duties included defusing land-mines before the infantry moved into the area. Brooks fought in the Battle of the Bulge in late 1944. Charles Durning, who plays the Nazi S.S. commander, Colonel Erhardt, was also a veteran of the Battle of the Bulge, and was present at the liberation of the Nazi death camp at Buchenwald.
The first Hollywood studio film to explicitly refer to the inclusion of gay men in the groups condemned to the Nazi death camps. The use of fabric patches by the Nazis to identify "undesirables" other than Jews is a historical fact. Pink and red triangles (depending on the region of Europe) were used to identify sexual deviants, predominantly homosexuals.
In an interview, Mel Brooks told the following story: "During the filming of a particular group scene, things were not going swimmingly, to say the least. Everyone seemed to be taking turns flubbing lines, laughing and joking, and Anne (Anne Bancroft) was getting a wee bit perturbed. Finally, she stood up and said, 'Let me remind all of you. I'm sleeping with the producer" (Brooks). Then she said, 'Okay, let's take it from the top!" Everyone just lost it, composure went out the window!"