I'll add to this - Air France is not ID90 anymore, they're ZED, with tickets issued electronically via the myidtravel link on travelnet, and DL employees get special lower-than-standard "JV Fares." You'll find departure taxes out of CDG are quite a bit more expensive than the ZED fare itself.

The one other thing I'll say about CDG is get there plenty early. I assume we're still using the AF check-in desks, and the queues last time I was there were quite long.