The RER (regional light rail) will be cheapest and at morning rush hour it will be fastest. It runs about every 15 minutes between 5:10 and 5:55 and every 8 minutes after that. It costs 7,75 Euro (each way). It takes 30 to 45 minutes depending on “where in Paris.” The RER station is in a building between Terminals 2D and 2E. If you arrive at Terminal 1 you will need to take the free shuttle bus (it is not walkable) — called VAL. It can take 10 minutes to walk and use moving sidewalks from the far ends of terminal 2A, 2B or 2G to the station. While the shuttle won’t be much, if any, faster than walking in, you may want to take it since you’ll probably be doing tons of walking in your few hours in Paris. I don’t believe terminal 3 (used by the budget airlines) has shuttle service, but info about CDG indicates 300 KM to the RER station, so walkable.

There is also the Air France express bus. It leaves from the same general area as the RER stations about every 20 minutes starting at around 5:40. I“ve seen it listed as 25 minutes “if traffic is clear” to at least an hour during rush hour. Other sources say 40 to 45 minutes — and I’d worry about it taking longer for your morning trip during rush hours. It costs 11,50 Euros.

Taxi will be very expensive (50 Euros each way) and will take as long as the bus. The only situation where a taxi would be faster would be if you arrived at Terminal 1 and could get a taxi from there.

Seriously think about what you want to see and do in Paris. If it’s a Monday or a Tuesday, find out if what you want to see is open that day. Here’s a typical 8 hour, early morning layover….

6:00 Land, clear customs and immigration
7:00 absolute earliest, 7:30 or 7:45 more likely: Get to Paris
9:00 Most things you want to see and do open
11:00 Head to your departure point to get to the airport, If you’re anal about not missing flights (I am) you’d be heading there at 10:45
11:15 absolute latest you can leave for the airport
12:00 Check-in (2 hours before flight)
14:00 Flight

Some airlines now recommend 3 hours advance check-in for an international flight….

Thanks for the tips. Its a Saturday that I will be there. I know the city fairly well and just plan to walk around; start near the Bastille for a baguette and some pastry and then walk down to Notre Dame and then toward the Louvre, maybe as far as the Eiffel Tower if I feel like hustling. If the trains are running at least every 15 minutes I think it will be worth my while.

Thanks again.