In the scene where Captain Gilbert and Lieutenant "Tex" pass each other in the main prison corridor, there are two mistakes. First, they are both wearing hats (per military custom, headgear is not worn indoors unless participating in a ceremony). Second, the two officers salute each other (saluting indoors is allowed only during ceremonies or when reporting to a superior officer in his office).
Near the end of the movie (the scene that the Nazi's receive their sentences), Each of the four judges are shown reading out at least one of the sentences. When the French magistrate is reading out a sentence, he lifts the sheet of paper that he was reading from, revealing several lines of highlighted text. This should not have been possible, as the first highlighter wasn't invented until 1962.
Most of the defendants used headphones throughout the trial to hear the translations of the Allied members of the court. Yet, none of the defendants used headphones to hear their verdict and sentencing.
As the camera passes Walter Funk when he pleads, "Nicht schuldig," Albert Speer lowers his headphones onto his shoulders. When the camera returns and it is Speer's turn to plead, the headphones are back over his ears.
At the Nuremberg trial, defendants gave their pleas of "Not guilty / Nicht schuldig" after moving to a single microphone at the center directly in front of Ernst Kaltenbrunner's position, rather than by standing at their places in the dock.
When the prisoners are giving their names, Field Marshal Wilhelm Keitel can be seen wearing an Iron Cross slightly larger than that of Alfred Jodl or Karl Donitz. This is because the Iron Cross he is wearing is in fact the Grand Cross of the Iron Cross, which should have been worn by Hermann Goring.
Many of the military courtroom guards are members of the U.S. First Infantry Division, as shown by their shoulder patches. They wear solid red shoulder cords (called fourrageres), which are apparently supposed to represent the French Croix-de-Guerre award won by the division during World War II. However, the red fourragere represent the Légion d'honneur, the 1st and 2nd US divisions were awarded the gold Fourragère aux couleurs du ruban de la médaille militaire.
The leading Nazis sentenced to death at Nuremberg were all executed during the night of 16th October in the prison gymnasium. Yet bright sunlight is clearly seen shining through the upper windows of the building as the condemned men are each brought to the gallows.