Paris Tourism Information Desk
If you are flying into Charles De Gaulle airport, I would sincerely suggest a stop at the Tourisme Information desk. Take advantage of this excellent resource of multilingual staffers ready to orientate visitors to Paris and its surrounding areas. You can pick up a free map, buy metro tickets, the Paris Museum Pass, book excursions and even hotels.
I personally like getting this all out of the way as soon as I get off the plane instead of running around Paris looking for ticket kiosks and tourist offices.
Charles De Gaulle Airport