Audrey Tautou revealed that, during her audition, she asked if she could take a photo of Ron Howard and Tom Hanks to prove that she'd actually met them.
To protect both the fabric of the building and the works of art it contains, the production's use of the Louvre Museum in Paris was carefully controlled. For instance, no equipment was allowed inside the Louvre during the opening hours, so filming took place at night. Since the crew were not permitted to shine light on the Mona Lisa, a replica was used to film instead. No blood or mysterious writings were permitted on the wooden floor of the museum, so these scenes were shot at Pinewood Studios, outside London. In the end, five replicas of the Mona Lisa were used.
When Teabing (Sir Ian McKellen) is describing the passage in the lost gospel of Philip, he is interrupted before he can finish quoting a line about Jesus kissing Magdelene. During an interview on NPR's "Day to Day," religious historian Elaine Pagels (whose book on the gnostic gospels was a source for Dan Brown's novel) said that the gospel is physically broken at exactly the place that Teabing stops talking, so he would be unable to quote it any further anyway.
Officials from Britain's Westminster Abbey refused to allow filming to take place in the Abbey, claiming that the book is "theologically unsound." Instead, the filming took place at Lincoln Cathedral in eastern England.
Because it was not certain that the movie would be a hit, and that other adaptations of Dan Brown's novels would follow, this movie was made as a stand-alone movie, rather than the beginning of a franchise. All references to the fact that Robert Langdon had already solved another murder riddle (in the novel "Angels and Demons", which precedes "The Da Vinci Code") were therefore purposefully left out of the script. When the movie was a huge financial success, production of Ángeles y demonios (2009) was started shortly after the release (but re-written as a sequel, not a prequel).
Dan Brown: When Robert Langdon is talking with the police during the signing party for his book. He is seen to the left of Tom Hanks immediately after the line, "We found your name in his daily planner." He is wearing the Harris Tweed jacket from his dust jacket publicity photo. He can also be seen a short time before, at five minutes and nine seconds, when the camera moves through the crowd of people. He is talking to a man, holding one of Langdon's books.
Cheryl Howard: (At four minutes and fifteen seconds) Ron Howard's wife can be glimpsed as an audience member (center frame, red shoulder-length hair) attending Professor Robert Langdon's lecture on Religious Symbology. (At five minutes and forty seconds) She can be seen clutching her copy of Langdon's autographed opus at his book-signing desk, and asking for him to sign his last book.