On a short layover in Paris CDG Airport you can do the usual like visit shops, and restuarants or just be bored sitting at your gate. But if you have a long layover at Paris CDG, I have something even better.
Long Layover at Paris CDG
Visit the Town of Roissy
Before our visit to Alsace, via a much cheaper train than SCNF, the national railway of France, we had some time to pass and did not just want to stay in the airport.
We decided to head over to the nearby town of Roissy France.
There is luggage storage in Terminal 1 and Terminal 2.
From anywhere inside the airport, take the free CDGVAL shuttle to Terminal 3

At Terminal 3, follow the signs to “Hotels by Shuttle”

You can take any of the free hotel shuttle busses – pink, black or blue. I took the black bus.

Get off at any stop. Wander the streets and take in French life outside the airport. We got off at Holiday Inn Paris CDG Airport and the town was only a 5 minute walk.

Walking around Roissy France
If you get off at the Holiday Inn stop, take a right and go for a walk through the Parc de la Mairie on your right where you will see the quaint town hall.

The small town is filled with buildings with flower boxes beneath windows and wooden shutters. Flowers hang from the lamp posts and life moves at a more leisurely pace.

and the remnants of a chateau from 1705.

Where to Eat in Roissy France
On the far side of the park, take a right on Avenue Charles De Gaulle and take the first left onto Rue Dorval. You will pass a bakery and a couple restaurants (which were closed on Sunday). At the end of the block turn right into the old Place du Pays de France. There you can find a Carrefour where you can get food and a bottle of wine for a picnic back at the park.
If you go the opposite direction on Avenue Charles de Gaulle, you will pass a couple restaurants if you want to eat; many were closed on Sunday but a lot of locals were seated at outdoor tables at Cinq J Pizza. There was also a creperie, Aux Trois Gourmonds, open on the left side of the street.

Continue a little farther down the hill to St. Eloi Church, dating from 1570. On the inside note the contrast between the simple architecture of of the main nave and the elaborate gothic architecture near the main altar.

When you are done, just walk back to the park and wait in front of the Holiday Inn. The bus will be by about every 20 minutes. You can get off at T2 or T3.
Aeroville Mall
From outside Terminal 3 (or some of the airport hotels), you can also catch a free shuttle to the Aeroville Mall. Look for the white bus that says “Aeroville”.

In addition to the usual mall shops (145 of them), there are 29 restaurants including fast food places, traditional restaurants and you can even grab a cup of coffee at Starbucks.
If you have enough time, you can even go to a movie at the cinema.
Free wifi.
10:00 a.m to 8:00 p.m.
Get Out of the Airport
If you have the time during a long layover at Paris CDG, don’t stay cooped up at the Paris CDG airport. Get outside and visit the town of Roissy. Or at least go to the mall. Just don’t sit around at your gate all that time.
Remember, the shuttle busses are free.