Hot answers tagged paris
Given that you didn't mention a method of transport... The easiest way to get from CDG to Gare Montparnasse without having to transfer is to catch the Air France Coach ("Les Cars AirFrance"), specifically coach number 4. Unlike attempting to catch the the train, these buses will pickup at all terminals at CDG (so there is no need to catch the airport ...
Your best bet using Paris transportation system : Reach the station located in terminal 2. Buy your ticket to Paris at the green machine if you have coins or a chip-and-pin credit card. Else you have to queue at the "regional" ticket booth, not the "grandes lignes" which is for long distance high-speed trains. A ticket to Paris is good for any destination ...
The RER B line does not go directly to Gare Montparnasse. You would have to transfer to the metro at Les Halles or Denfert Rochereau (or possibly a couple of other places, see the metro map). You could transfer to metro line 4 as early as Gare du Nord, but the RER is much faster than the metro when going through the city.
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