Brian De Palma took the idea of the train station scene from the Russian movie Bronenosets Potemkin. The sailors who get caught in the crossfire in this movie are a tribute to Potemkin.

When Ness and the bailiff remove Frank Nitti from the courtroom, on account of Nitti wearing a concealed firearm, Nitti produces a permit in the form of a carte blanche (please extend to the holder of this card, Frank Nitti, all courtesies) signed by Chicago Mayor William Thompson the Mayor.