When Miss Simmons is reading the letter from "Sweet Thing" she says "But I still remember" where the letter actually reads "but I've never forgotten".
At the beginning of the film, the news report mentions the radio station as WRIX. However, when Leon gets fired, the sign on the building says WNKW.
When Sofia Milos' character is shown as nude, pasties are clearly visible. They aren't even "flesh" coloured.