Factual error: In the opening scenes at the nightclub when Oscar is treating his new friends to dinner, they are singing "The Happy Wanderer" ("Der Fröhliche Wanderer"). This song was written by Friedrich-Wilhelm Moller shortly after WWII. The nightclub scene was supposed to have taken place in 1939.
Factual error: During the liquidation of the ghetto, many German soldiers shout and beat the Jews out of their homes but one of the soldiers salutes a little child saying "Wie heisst du?" (What's your name/what are you called?). However the subtitles from the Deluxe Edition DVD read "hiesst" instead of "heisst" (which is not even the preterit/past form, which would be hieß/hiess).
Factual error: There is a scene in which blues singer Billie Holiday is heard singing (presumably on the radio) her song, "God Bless the Child." Holiday did indeed first record this song in 1941, but the version heard in the film is from much later, after the war, in the 1950s (It is believed to be a version which was recorded for the Verve label). The version which should have been heard in the film was recorded in 1941 for the Okeh label, and is now part of the Columbia Records catalog.
Factual error: Steven Spielberg didn't get permission to shoot the train arrival at the real Auschwitz. So he build the main entrance, but seen from the front side. The gate, left from the main gate proves that. So when the train 'enters' at Auschwitz, it in fact is departing Auschwitz, instead of arriving. Eleven minutes later, it's just the other way around. When the train departs, it's actually 'arriving'.
Factual error: When Amon Goeth attempts to execute the Jewish factory worker for failing to produce enough hinges, Goeth cycles the actions of both inoperative weapons several times. At no time is an unfired round ejected from either handgun, which should have occurred, unless the unfired rounds were both jammed in the chamber (and the firing mechanisms had failed).