I had good luck the last three times I connected through CDG. The first two were eastbound, IAD-CDG-NCL and IAD-CDG-EDI. I did not have to change buildings, as the onward flights boarded from bus gates in what is now called the K building; the only pain is having to reclear security there, but the "Acces 1" lane shortens the wait.

The other time was westbound, ZRH-CDG-IAD; the Avro-85 regional jet parked at a remote building, T2G, where they looked at my passport but didn't make me reclear security, and then I took a bus to the K building, where my onward flight to IAD was parked (and, of course, there was an AF Salon).

Where things pile up is having to go from the arrival gate to the Schengen gates for the onward flights (I get the terminals 2E and 2F mixed up in my head). You have passport control and having to reclear security in this corridor which connects the two terminals; if you arrive at 0530, which is common for flights from places like IAD, only a couple of border police are manning the booths, and this can cause a delay for a couple hundred passengers or more; the full complement of border police don't show up until 0600.