Continuity mistake: Agatha's nightgown strap switches between hanging down on her arm, or being up on her shoulder, normally.
Continuity mistake: When Zero and Mr. Gustav are discussing things in the courtyard right after Mr. Gustav escapes from through the sewer system, Zero's bag strap switches between across his chest and hanging by his side in different shots.
Factual error: The concierge in 1968 rushes to help a guest who is choking. The scene depicts him performing the Heimlich Maneuver. It was not introduced until the 1980's.
M. Gustave: You see, there are still faint glimmers of civilization left in this barbaric slaughterhouse that was once known as humanity. Indeed that's what we provide in our own modest, humble, insignificant... Oh, fuck it.
Zero: What happened?
M. Gustave: What happened, my dear Zero, is I beat the living shit out of a sniveling little runt called Pinky Bandinski, who had the gall to question my virility. Because, if there's one thing we've learned from penny dreadfuls, it's that when you find yourself in a place like this, you must never be a candy ass; you've got to prove yourself from day one. You've got to win their respect. You should take a long look at HIS ugly mug this morning. He's actually become a dear friend.