What do you want to know? Deviating into CDG? Spent all your DEV bank on a limo to work? Second cheapest option for getting from term 1 and 2 at CDG to (most) of our downtown hotels. (the cheapest BTW, is an RER ticket which can be purchased for 9.5 euro).
For the bus, the hardest part is finding the right location around the terminal. Make sure you get the LES CARS/AirFrance bus #2 and get off at the Porte Maillot stop. Hotel is next to the stop. I think the fare is 16 euros but I could be off a couple. Pay the driver with CASH.
Bus #1 goes to the Gare de Montparnasse, which is by our Montparnasse hotel, I believe across the street. Bus # 4 goes to the Gare de Lyon, which is not next to the Bercy hotel but a nice walk (20 mins) or two subway stops away. Enjoy!