Charles de Gaulle logistics for a layover

This question comes up frequently. No. You don't have time. You will miss your flight. If you have to be back at the airport three hours prior to your flight, that leaves two and a half hours if your plane's on time and if you can poof yourself from the plane to the train - - you'll be lucky if you can make it to the trains within an hour of the door opening, but we'll just ignore that. The train ride is about an hour and fifteen minutes each way, plus a ten minute walk from the metro station to the tower. That's your two and a half hours right there - - now go back and plug in the time to get from the plane to the train. The next noise you hear will the sound of a Rome-bound plane passing through ten grand. A taxi might be fifteen minutes shorter each way, or it might be fifteen minutes longer -- who knows. The inbound surface traffic can really suck at mid-morning.

I also replied to your itinerary post. You really don't have 5.5 hours to kill, because you still have to get off the plane, go through passport control, and get to the next gate (at least an hour, at CDG this can take even longer). Plus, you need to check in at your next gate (an hour ahead, to be safe). That's about 3 hours of down time. I'd consider looking into buying a day pass to the Delta sky club lounge (or one of their partner airlines) at CDG. They have snacks, showers, and comfortable chairs.

Thanks for the feedback, it really helps.

The air france lounge is amazing! CDG can get really warm because of the glass top and the lounge is downstairs, air conditioned with lots of food & drink.