Paris -

I think you will find that Bordeaux isn't really convenient to travel to from Barcelona. The main train route from Barcelona to Paris passes along the Med, through Avignon. Train service from Barcelona to Bordeaux is difficult but possible. The flight from Barcelona to Paris is much shorter, but you won't be able to stop in small towns/cities.

You could easily add at least a night or two to Barcelona and not run out of things to do. Along with the attractions of that city, itself, there are numerous terrific day trips you could take.
Wherever you decide to stay before your flight home, it wouldn’t hurt to allow 2.5 - 3 hours at CDG for all the processing, less without checking baggage. The last time we did it, we allowed 2 hours and boarding had begun when we reached our gate. (That was with checking bags.)

Your updated post isn't very clear about your plans.

I may just exit from Paris and only spend one night.

Does this mean you want to spend only one night in Paris and then go by train to other places? Or does it mean you want to take overnight trips by train from Paris and then back to Paris?

For the latter, this book might give you some ideas. It's ten years old so some of the train info may be out of date, but the author has spent a lot of time in France and has very good ideas. Though she considers some of the destinations as day trips, any of them could be overnights.

When is the trip?

If I remember correctly from your other post, your trip will be in September (?) and you'll have about 10 days (?). Looking at where you've been before I would recommend somewhere in either Normandy or Brittany. My choice would maybe be Rennes in Brittany because it's easily reached from Paris by train and has several good day trip possibilities by train or bus - Mont Saint-Michel, St Malo, Dinan, Fougeres, and several others.

It might help people a little more if you gave some indications of what you like to see and do - what are your interests? And maybe clarify your amount of time and what time of year.

When is your trip? How long do you have ?

For a 10:30 am flight, you will need to be at CDG at 7:30 during normal times, and perhaps 6:30 during Covid times. I would stay at an airport hotel as that is going to be a very early start.

There is no town but Paris in easy train to CDG. I would just plan to arrive late at the airport the night before and stay in an airport hotel. AT not near the airport. We stayed at the Novotel in November which was cheap, had a good breakfast and is right on the shuttle train that connects the terminals. It was a VERY long walk from the shuttle station at Terminal 2 to Terminal 2A where our flight departed. Next time I will just take a cab at the crack of dawn which will deliver me right to the door of the Terminal I need.

WE do side trips now from Paris when we do extended stays. This year it was Lyon which you have seen. A few years ago it was St. Malo and we based there for several nights and then took the train to Auray where we booked a guide to the neolithic sites since we no longer drive. St. Malo is well connected by bus (in summer by boat) to many towns in the area including Dinan. There is a daily bus to and from Mont St Michel but we had done that on an earlier trip so didn't do it from St. Malo. And we walked to St. Servan. We really loved it. St. Malo is gorgeous; there are tons of inexpensive apartments. Although on this short trip we ate dinner out (St. Malo has fabulous restaurants -- reserve a day or two ahead) but it was fun to go to bakeries in the morning for the wonderful regional specialties to bring back to the apartment for breakfast.
https://janettravels.wordpress.com/category/brittany/
Another side trip we did was Angers and Nantes -- loved that as well. https://janettravels.wordpress.com/2019/09/13/les-machines-de-lile-nantes/
The castle in Angers is stunning and contains the Apocalypse Tapestries- a hundred yards or so of amazing tapestries -- and actual tapestries unlike the Bayeux Tapestry which is amazing but not a tapestry.