Errors in geography: The northwest corner of the concentration camp map, around Belgium and the Netherlands, shows about three extra countries.
Continuity: The US Army collar insignia appears, disappears and reappears sometimes in the same scene.
Factual errors: The actual text of the Nuremberg Law ("Law for the Protection of German Blood and German Honor", promulgated September 1935) only prescribes a prison term as punishment for "extramarital intercourse between Jews and subjects of the state of German or related blood", not death as stated in the script. So Mr. Feldenstein could not have been sentenced to death by a German court. Unfortunately, this would not have prevented the Gestapo from arresting such people and sending them without a legal trial to a concentration camp, where death was a very likely outcome. The Nazis rarely bothered with trials in such matters.
Errors in geography: On the concentration camps map, the town of Natzweiler/Natzwiller (Camp Struthof) is situated in Baden/Germany, while in reality it is in Alsace/France.
Factual errors: At the end of the film, there was a notation that stated there were 99 defendants at the Nuremberg trials who received prison sentences, but by the time the film was made, all of them had been released. However, Rudolf Hess, at one point third in line in the German leadership behind Hitler and Goering, remained in prison until his suicide in 1987.
Errors made by characters (possibly deliberate errors by the filmmakers): When William Shatner's character (Capt. Byers) swears in Montgomery Clift, the Clift character (Peterson) fails to use the headphones, yet answers the question as if he understood the oath. There was no indication that Byers spoke German nor that Peterson, who was feeble minded, spoke English.