Hello You can also follow the signs at the airport with "Paris by Train", and use the RER B to get to downtown Paris in about 30 minutes. This is quite cheap as well. The RER B stops at the following metro stops: Gare du Nord, Chatelet-les-Halles, Saint-Michel/Notre Dame, Luxembourg, Port-Royal, Denfert-Rochereau... If you take the metro to Chatelet-les-Halles it is not to far away from the Louvre Museum. or you can change metro line there and take it to Palais Royal, the closest metro stop to the Louvre Museum.... God luck Some useful links: Paris Metro map - Charles de Gaulle to Paris.

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