In Paris, almost everything is around the Louvre, where the professor Robert Langdon is called in after a murder. Start with the Grande Galerie of the opening chase, then go out to the glass pyramid and down to the Pyramide Inversée, the upside-down pyramid in the Carrousel du Louvre that is the film's last image. The Pont du Carrousel, where the police chase a decoy while Langdon and Sophie escape, is a two-minute walk.
At the end of the film Langdon follows the Rose Line, a line marked by small brass medallions in the pavement. To walk it, start at the Ritz on Place Vendôme and head to the Palais-Royal, looking for the medallions in the courtyards and under the colonnade, then cross Place Colette to the Louvre: about 15 minutes in all. Saint-Sulpice is across the river, 15 to 20 minutes from the Grande Galerie. The Montmartre street where the killer monk Silas hides is a separate trip by metro. One day covers all of Paris.
Inside Saint-Sulpice, look down: the brass strip in the floor is real. Rue Becquerel is a quiet stepped street with a rare view of the back of Sacré-Cœur, and Amélie is about five minutes away on foot.