Originally Posted by
RatherBeInYOW
You have to do it landside. There is a little train called CDGVAL you can take that will take you from T2B/D (near the main train station, there are signs) to T1 - probbaly 15 mins or so but then you need to reclear security etc. CDG is brutal for connections unless you are going AF to AF inside T2.
Don't need to take the CDGVAL to change terminals if you're airside. There is a shuttle bus that runs in a loop between every terminal. Once you're airside at Terminal T2B, follow the signs to Terminal 1. Runs every 10 minutes or so....