Factual error: In the book Teabing is a die hard British patriot, yet he refers to the sport of soccer. NO Englishman would use the word soccer for the game of football. [People keep trying to correct this - you've really got to accept it. It's nothing to do with Teabing being older - soccer may have been used in the very early days of the game, but the governing body of the sport in the UK is the Football Association, formed in 1863, demonstrating how that was the accepted word for the sport even then (otherwise it would be the Soccer Association). Likewise the international governing body, FIFA (Fédération Internationale de Football Association), formed in 1904 - no mention of the word soccer there either. And it won't be him changing it for Langdon's benefit, considering a) Langdon's intelligent enough to know what he means, and b) he's so determinedly English about everything else. This site is run by a Brit, and it's not getting changed. :-)]
Factual error: During the car chase in Paris, Langdon and Sophie head for Champs-Élysées to get to the American embassy before they turn for the train station Gare Saint-Lazare. Since the embassy in question is located at the north of Champs-Élysées near the Louvre that means they actually have already passed by the embassy while supposedly en route to it. This has been corrected in the French version but not in the English.
Factual error: Teabing tells Remy to park on the Horse Guards Parade where it offers wonderful views of Big Ben and the House of Parliament. No it doesn't. Downing Street and the Ministry of Defence would block the view. Plus he can see the Temple Church from across the lawns and the pond. This is in the wrong direction. If he's looking across the park from where he's parked he would be able to see Buckingham Palace. There are a lot of buildings in between Teabing's position and the Temple, and there are no parks between the two.
Factual error: Silas has severe albinism. He should be legally blind. People with even mild albinism have impaired vision due to lack of retinal pigmentation. There is no way Silas would be able to fire a gun over a distance with any accuracy, or drive a car, yet he does both these things. There is never a hint or comment anywhere about his poor vision.
Factual error: The book makes the point that Jesus would have to have been married, since it was extremely unusual for Jewish men in their thirties not to be married at that time. This is completely false, it was no more uncommon than it is today. In fact, out of the twelve apostles, only Peter had a wife.
Factual error: There is no hand on the Last Supper painting which doesn't belong to anyone. The hand holding the knife is the hand of Simon.
Factual error: When Robert Langdon and Sophie Neveu arrive at Leigh Teabing's estate in chapter 52 there is a reference to the right-hand side of the vehicle being the passenger's side everywhere in Europe except England. This is incorrect, as it is the driver's side in the whole of the United Kingdom (England, Scotland, Wales and Northern Ireland) as well as in the Republic of Ireland.
Other mistake: Langdon and Teabing make a point of how John the Apostle looks female in the painting The Last Supper, and claim that it shows that it was not John at all depicted by Mary Magdalene. During Da Vinci's time it was actually common to portray John with long hair and no beard as he was thought to have been quite young when he became an apostle. Furthermore, Da Vinci painted The Last Supper using a new type of paint, which unfortunately did not stand the test of time very well. After only a little more than half a century most of the color had faded and the painting had to be restored. Any female traits in John's face may be the result of whoever restored the painting, not Da Vinci himself.
Factual error: The floor in front of the Mona Lisa in the book is described as being black-and-white parquet. In reality, it is hardwood, as are most of the floors and hallways in the Louvre. Further, the Mona Lisa isn't located at the end of a long hallway; it is in a smallish room which branches off the side of a long hallway, along with several other paintings.
Continuity mistake: Robert Langdon has a lot of problems with the manual gearbox of the car that they're driving. However, in the book "Angels and Demons" he doesn't have any problems with a car he's driving in Rome. Although this could have been an automatic, you should realize that such cars (especially older ones) are not very common in Europe.
Factual error: At the beginning of the book, it explains how Silas escaped from a French prison in Andorra. Andorra is an independent country and does not hold any French or Spanish prison.