Originally Posted by
aliv
Go and see Paris! While there are no luggage lockers at CDG, they do have them at the Gare Nord where the trains from CDG arrive. It takes about 30 min to reach downtown from the airport. From there, you are about 20 min walking distance from Louvre and all the great things Paris have to offer. Train interval is 10-15 minutes, so you should be ok.
Much as I love Paris, this seems awfully ambitious.
From arrival time to the train, it could easily be an hour for walking, immigration/customs, etc. Even without immigration and customs, it can be close to 30 minutes, depending on where you arrive. Then add getting tickets, maybe a short wait for the train on both ends and the 1-hour round trip, plus some time to check back in at CDG and go through security - seems like you'd have no more than 30 minutes in Paris after all that.
If the OP goes with this ambitious plan, I'd suggest getting off at the St. Michel-Notre Dame stop, not Gare du Nord. You'll be in the shadow of Notre Dame, and only 5 minutes from the Louvre. With such a short stay in Paris, those extra few minutes would make a difference....