Factual error: When Cruella first drives her iconic car, being in Britain the driver's seat should be on the right side, not the left.
Suggested correction: Cars can be imported from overseas. It's very possible the car was imported from America.
Continuity mistake: In the scene about the upcoming show the Baroness states she needs 12 key looks. She turns to count what she has and pulls down 10 looks that fill the board. When she turns back to face the staff she comments on the need for 10 looks.
Factual error: When Cruella as a child makes her way to London and crosses the zebra/pedestrian crossing, there are visible zig zag markings. These however were not introduced until 1971 in England, which is the time period when Cruella is older.
Continuity mistake: At the Black and White party, when Cruella is taken to the Baroness, the position of Cruella's right hand has no continuity whatsoever in any of the shots.
Continuity mistake: When Horace exits the Black and White party, the amount of cake on his face is inconsistent between shots.
Revealing mistake: Right after baby Estella is born there is no umbilical cord.
Character mistake: Whenever Catherine visits the Baroness with young Estella, before she gets murdered, she asks the Baroness for money so that her and Estella could start a new life. Since Estella is being spoken about, the Baroness is aware of her at this point. However, later on in the movie, the Baroness questions John, "What did you think I meant when I said take care of the problem?!" Implying she thought Estella had already been killed when she was a baby.
