If you're at CDG just for a stopover and don't have much time, you might want to check out the window front between Aerogare 2D and 2F. You can take good pictures of traffic on the west apron of 2F (mostly A32X and 73X) as well as of moevements on the taxiway between the south runways, Aerogare 1 and the north side of Aerogare 2 from here. And the best aspect about it in summer: it is airconditioned and facing north! You will need a 70 to 300mm zoom here.
If you leave Aerogare 2A and follow the street ramp to the left until you get to the commuter airliner parking, you can take pictures of traffic using the taxiways betwen Aerogare 1 and 2 from here. You're going to need a 100mm zoom for the commuter parking and 200-300mm for the taxiways.
There are some other good places at CDG, but you're going to need a car to get there, and I can't tell you, how good they are, because I haven't been there yet.
Homer: Facts are meaningless. You could use facts to prove anything that's even remotely true!