Yes, I agree with halibut. CDG is NOTORIOUS for its grueling non-revving procedures. They close the flight 45 minutes before (the standard for most international flights) and you can not get on the list for anything if you show up after they close the flight, so don't even try it. No go. Most of us avoid CDG like the plague. Also, remember that as a buddy pass rider, you are no longer able to fly on other codeshare flights (other airlines) even if they have a Delta flight number on it. You can only fly on Delta metal.
Also, it may be easier to ask the employee who gave you the buddy pass to check on flights for you 1-3 days before for a better idea. If you need any help with that, feel free to contact me and I can help you with that off-line.
Good luck!