I must go from CDG 2 Airport to Paris Massy TGV. Is there a RER B direct? What´s the price of the ticket? Can I buy it on-line? Thank you!! Gabriel
Yes there are direct RER B trains from CDG T2 to Paris / Massy TGV station.
After you buy RER B tickets (13.10€, can't buy RER tickets online) and make your way to the platform, be sure to board a train that goes to destination of either Massy-Palaiseau or St Remy les Chevreuse. Do not board a train for Robinson.
Massy-Palaiseau is connected to the Massy TGV station. Travel time is about 72 minutes.