When Hepburn finally reunites with her father, she leaves estranged. In reality, she maintained in touch with her dad until the end of his life.
The filming of the start and end sequence of Breakfast at Tiffany's (1961) is out of sequence and nothing like the original film
Audrey Hepburn's full name was Audrey Hepburn Ruston. Thus, she would have used the last name Ruston in her younger days, and her father would be referred to as Joseph Ruston. Not, Joseph Hepburn.
Audrey Hepburn left Arnhem in 1942 for nearby Velp; the city of Arnhem was virtually flattened in 1944, so when it was liberated, there were no buildings standing. The film shows a city being liberated with buildings everywhere.
When a scene from Sabrina is recreated, "Bogart" kisses "Hepburn" by a swimming pool, but in the real 1954 version it takes place in a tennis court.
When Audrey receives the letter from her father at the hospital, she appears to start reading the letter on the back instead of the front. Then in the next shot she holds the letter correctly. She isn't trying to read the letter but checking for her father's signature at the end of the letter to confirm it is actually from him.
When Audrey is auditioning for the ballet school in London in 1947, there is a close-up of a pair of feet wearing pointe shoes. Unfortunately, these feet are wearing Gaynor Mindens, pointe shoes not introduced to the world until the late 1990's, shoes that, because of the very advanced methods in their construction, are controversial in the ballet world to this day.
Churchill's famous "so much owed by so many to so few" speech was broadcast in August 1940 after the Battle of Britain, not in September 1944 after the liberation of Holland.
The day Holland is liberated, Audrey was sick and almost died in the story. Later in the film she tells someone about that day and how wonderful it was to watch the movie in the middle of town to celebrate. She was too ill to get out of bed and would not have been able to attend.
When Audrey is being tailored for a pink dress, and is talking to Givenchy about her neck being "too long", you can see a boom mic in one of the mirrors behind them.
In the movie Truman Capote complains, that Audrey in the part of Holly Golightly in "Breakfast at Tiffany's" get a song. He says: "Call girls don't sing." But in his book, the movie based on, Holly Golightly also sings, so it's unlikely that Capote really said that.