metro from CDG to Paris

It has been a couple of years since we were in Paris. But you need to take the bus from CDG to the train station (5 min ride) and the RER>Metro into Paris. You probably will have change train for that stop. If you don't have the metro map I can check mine. Have to find it first.

I did this two years ago, we stayed a Hotel Eiffel Rive Gauche, and I think we took:
rer line B to Gare du Nord then Metro 4 to Strasbourg-Saint Denis and the metro 8 to Ecole Militaire. If I remember correctly it took almost 45 minutes though... When you get there talk to a person at one of the RER ticket booths they are extremely helpful! Also if you are in contact with your hotel/hostel, they would probably give you really detailed instructions as well.

Alan: Here's another way. Get off the RER at Gare du Nord. At the back of the Gare is a bus terminal. Take Bus No. 42 (it is the beginning of the route so lots of room for your luggage) and get off at Champs de Mars. You are now within walking distance of the Ecole Militaire metro stop. Of course, you will have a map with you.

The method may have changed. Go to the Tourist Information Office at the CDG terminal and ask the best way to get to that stop and get a bus and metro map.

Indeed, the method has changed. While there still are airside buses that go between the sections at Terminal 2, the inter-terminal shuttle buses have been replaced by the 24/7 CDGVAL driverless shuttle train.

If you arrive at Terminal 2, take the RER B from CDG 2 TGV. The station is directly below the terminal. If you arrive at Terminal 1, take the CDGVAL to the CDG 1 RER station which is located next to Terminal 3. For detailed instructions, with photos, go to the Parisbytrain site.

Take the RER B to St-Michel Notre-Dame. Transfer to the RER C and take it to Invalides. Transfer to Metro line 8 and take it to Ecole Militaire. For a zoomable map of the Metro and RER system, go here. The fare is €8.40.