Geli's lines when she is smoking with the driver, just after being told her uncle is "a good man", ("he's a monster... you can't imagine what he asks of me") are Geli Raubal's actual words, taken directly from her journal. Allegedly, Hitler drew a series of pornographic sketches of her, entitled "Miss Raubel in close-ups and angles to which any professional model would decline posing for."
All Nazi-themed costumes and props (flags, medallions, pins, tie-tacks) were destroyed after filming wrapped, to prevent any items linked with Nazism from finding their way into the hands of neo-Nazis.
In March 2003 while shooting the scenes in Prague on Wenceslas Square, near the National Museum, the movie crew had to put some vehicles in the background to hide candles and flowers laid on a pavement in commemoration of Zdenek Adamec, who committed suicide by self-immolation as a political protest several days before the shooting had begun. Exactly in the same place, exactly in the same way and exactly with the same purpose Jan Palach put the end to his life 34 years earlier.