Expect to pay about 150 francs for a two-hour tour.
Reservations are necessary.
Tickets are good for unlimited use for two days and cost 125 francs. Tours are often restricted to 30 people and are popular with Parisians as well as tourists. They are accompanied by guides whose enthusiasm and dedication is invariably exemplary, though most are French and may not be able to communicate their enthusiasm to you in English. These potential linguistic problems are more than outweighed by the chance to see Paris in a new light and to visit buildings and monuments that are not usually open to the public. Charges vary between 40 and 60 francs, depending on fees that may be needed to visit certain buildings.