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.
When the prosecutor Hans Rolfe (Maximilian Schell) is questioning a witness, he first asks if the had sworn to "The Civil Servant Loyalty Oath of 1934". However, then the prosecutor's assistant is asked to read the oath from "The Reich's Law Gazette, March 1933".
Right after Richard Widmark states that "the defense rests", he sits down next to his assistant attorney. A moment later the assistant's arms have changed position and Widmark's hands have changed position.
Right after Rolfe completes the quotation from Oliver Wendell Holmes regarding sterilization, we see Haywood with his hand on his mouth. The wider shot that follows shows him with his hand on his cheek.
When Colonel Tad Lawson (Richard Widmark) makes his opening address to the court he screams about (Nazi German) judges in their "black robes". This is incorrect. German judges wear red robes - American judges wear black.
At the night club, when the reporter Max Perkins tells Judge Haywood that he couldn't give a story away on the trials because the American people aren't interested, Haywood remarks, "But the war's only been over for two years," to which Perkins replies, "That's right." The film's opening title card says "Nuremberg 1948" - three years after the end of World War II. The actual Judges Trial, upon which this film is based, was held in 1947. It is likely that the title card is incorrect.
The housekeeper, Mrs. Halbestadt, says that Mrs. Bertholt's husband was executed in connection with the Malmedy massacre during the Battle of the Bulge. Although many Germans were found guilty for the massacre and some were sentenced to death, none of then was ever actually executed.
At the end of the movie a graphic states that 99 people were tried and sentenced at Nuremberg and that by the date of the movie (1961) none remained in prison. Some critics have pointed out that Deputy Fuehrer Rudolf Hess was tried at Nuremberg, found guilty on two of four counts charged (crimes against peace and conspiracy) and sentenced to life in 1946. He died in 1987 still imprisoned in Spandau Prison. Yet the caption in the film states that the statistic refers only to the Nuremberg trials "held in the American sector." Hess and the other major defendants were tried by the International Military Tribunal (with judges and prosecutors from each of the four victorious Allied powers). After this major trial, other trials were held in each of the four occupation sectors. By 1961, all of the defendants sentenced in the American trials were indeed free; the graphic is therefore correct.
The American judges and German defendants speak through an interpreter. At first, there is a substantial delay in the dialogue while the translation takes place but eventually the reactions becomes nearly instantaneous (for example, when the judge says "You may be seated", the defendants sit down right away without waiting for translation). The translation delays were likely dropped to keep the movie from dragging.