Yes, you go down escalators and walk underground then back up. It's no more than 5-10 minutes. Heres a map: http://www.aeroportsdeparis.fr/Adp/R...2b4-cdg2ef.pdf

Here's also the sticky thread from the Air France forum with all you'll ever want to know about CDG
http://www.flyertalk.com/forum/showthread.php?t=456112