Discounting the silly little continuity errors like props moving around from scene to scene and skycover clouds flipping about...
People who've actually been to Rosslyn (the correct spelling, though it is in the village of Roslin) Chapel will be amused to see in the movie that Tom Hanks and Audrey Tautou were somehow able to bypass the many security guards, the gift shop, tea room, museum and admissions desk to get into Rosslyn, and also that they did so via a door that is always locked beyond two stout gates. No one ever enters Rosslyn the way they did.
In the Louvre, Sophie puts the GPS receiver in a bar of soap and tosses it out the window onto a passing truck. Problem is, the bathrooms in that part of the Louvre don't have windows... nor do they have bar soap. Its all liquid.
When they are arresting Teabing the policeman says the Miranda warning, which is used in the USA, not England.
Sophie flips in and out of English notational a few times. She speaks of 'x' many miles to the gallon... and '2 miles to the embassy'. The French have been under the metric system for 200 years. Why would a French national even have the inkling to use such terms?
One of the main features of the Chapter room in Westminster Abbey is the tiled floor - the tiles are red, small and octagonal, and hand painted. In the movie, they're big, plain bricks.
Teabing at one point makes the comment that the Bible refers to the cup used at the last supper as the Grail. The Bible does not do this. It gets no mention at all, actually. It was not for several centuries, until the romance of the Grail was written that the cup is given 'magical' powers.
When Teabing is almost arrested by British police at Biggin Hill, all the police are armed. Throughout all the shots, however, the windshields of the police cars are blank. All cars that carry armed police have three yellow dots on the windshield.
Captain Bezu Fache of the Direction Centrale Police Judiciaire (DCPJ) is sure that Langdon is the murderer. Fache has one of his lieutenants plant a GPS dot in Landon's pocket. It's a "metallic, button-shaped disk, about the size of a watch battery." This dot, according to cryptographer Sophie Neveu, is accurate to two feet and lets the DCPJ track Langdon's location, no matter where he is. In other words:
It's tiny.
It's amazingly accurate.
It works indoors.
Can be small, but they're usually bigger than a watch battery. The unit described in the book would also have to fit a power source and a second radio transmitter into its tiny shell in order to communicate with police computers.
Are accurate to somewhere between 13 and 328 feet (4 and 100 meters).
Don't work well indoors, under dense tree cover or in urban areas with tall buildings.
"Virgin of the Rocks" hangs in the Grand Gallery, not the Salle des Etats. The painting directly across from the "Mona Lisa" is Caliari's "The Wedding Feast at Cana." This painting is an enormous 32 feet (9.9 meters) wide. To be fair, we have not found a source detailing which painting faced the "Mona Lisa" before the 2001 closure of the Salle des Etats. However, in several older photographs, reflections in the "Mona Lisa"'s protective glass indicate that it wasn't "Virgin of the Rocks."
Even if "Virgin of the Rocks" did hang opposite the "Mona Lisa," it's 6.5 feet (1.99 meters) tall, too tall for Sophie to see over as described. The painting's ornate wooden frame is also too heavy for an average person to lift unassisted.
Sophie's removal of the painting from the wall does not activate any sort of security system. This contradicts the beginning of the book, in which Saunière removes a painting from the wall to activate a security system that seals off an entire corridor. It also contradicts the Louvre's real security system, which includes proximity and movement detection. For the record, this security system also uses real security cameras, which staff monitor 24 hours a day.
When traveling from the Paris Ritz to the Louvre, Langdon and a DCPJ agent pass the Opera House and cross Place Vendôme. However, the Paris Ritz is on Place Vendôme. In order to pass the Opera House, the officer would have to head in nearly the opposite direction of the Louvre.
Langdon says that Saunière, a devotee of the ancient "sacred feminine," was interested in Wiccan relics. However, Wicca is a modern religion, not an ancient one.
The pyramid entrance to the Louvre contains 793 panes of glass, not 666.
Tarot decks contain 77 cards, not 22, although a deck does have 22 major arcana cards. Check out How Tarot Cards Work to learn more.
Phi is an irrational number. It's more accurately expressed as (1+√5)/2 than as the number 1.618.
The first of the Dead Sea Scrolls was discovered in 1947, not the 1950s.
The novel implies that the Louvre has one curator. It really has a staff of 60 curators in eight departments. The "Mona Lisa" has its own curator.
Harvard does not have a professor of "symbology," and symbology is not a real academic discipline.
There are no metal detectors at Westminster Abbey, and people cannot make charcoal rubbings of the plaques there.
(some of it is my words and stuff lifted from at least 3 other sources melded together)