Alec introduces his new song, " Do I love you", to May in her dressing room saying he wants her to be the first to hear it. After he finishes he is called to do his number on stage where he dances to a chorus and band playing "Do I love you".
During the Du Barry bedroom scenes, Lucille Ball, playing Du Barry, can be seen wearing flat-heeled shoes while yelling at the guards, being chased around the room, and then hopping around on the bed. Then she is wearing strappy shoes with a small heel.
At one point during May Daly''s opening song, Louis is sitting behind the hat check counter admiring her. He has his chin resting on his left hand, which he removes twice when someone come up to the counter.
(around 61 mins, 30 seconds) When Louis XV leaves his bedroom to go to another room, he opens the door with his left hand. But the next cut being a reverse shot, it shows that he has opened the door with his right hand.
During the scene in Madame Du Barry's boudoir when King Louis XV is chasing Du Barry around on the bed, you can tell the bed is a trampoline under the bed spread.
When Red Skelton wakes up as King Louis, Douglass Dumbrille introduces himself as "the Prime Minister of the Empire of France." But France was only a kingdom in Louis' time. It didn't become an empire until the time of Napoleon.
The Black Arrow (Gene Kelly) is condemned to die via the guillotine. But this story is set around 1770, during the reign of Louis XV--and the guillotine wasn't introduced until 1792, during the reign of Louis XVI, over 20 years later.
During the scene in Madame Du Barry's boudoir when King Louis XV is chasing Du Barry around the dressing table, a man sitting in a chair can be seen reflected in the mirror.