One reason "The Da Vinci Code" feels like a more prestigious movie than run-of-the-mill conspiracy films is because it takes place at many fancy real-world locations that do not normally allow movies to shoot on their premises. But when you have Tom Hanks and filmmaker Ron Howard attached to the project, doors tend to open invitingly.
Case in point, the Louvre, possibly the most swanky museum in the world. "The Da Vinci Code" starts with a murder at the Louvre that has baffled the police. Instead of recreating the museum on a Hollywood stage, the makers of the film decided to go straight to the source. The caretakers of the museum agreed to allow filming on the premises, provided strict precautions were taken during the process. "It was complicated," admitted Henri Loyrette, the president-director of the Louvre, to The New York Times. "It involved enormous preparation. But things worked out very well."
The film crew was only allowed to shoot at night. None of the artwork could be touched or directly illuminated. Blood or any kind of marking was not allowed to deface the floors, and even food and drink could not be brought into the museum for the crew. According to Ron Howard, the various restrictions actually ended up working in their favor, since the low lighting added to the mysterious ambience of the film's opening scene.