ATM in Charles De Gaulle Airport

The exchange rate is set by credit card network and not the bank so it makes no difference which bank owned ATM you use as the rate would be the same. If you use a currency exchange ATM (and they try to make them look like a bank ATM) then the currency exchange company will set the rate. Those should be avoided. Most European banks do not charge to use their ATM (unlike the US) so bank owned ATMs should be free. Fees are disclosed if you find an ATM charging fees. Also, be aware, that all of the additional fees for using a debit or credit card are set by your card issuer.

Keep in mind that the exchange rate varies by the minute so even if you used the same ATM in the morning and afternoon you could get a slightly different exchange during the day.

Your own bank makes a difference, and you haven't told us what that is. But, for example, while Bank of America waives the fixed fee in France at (AFAIR) BNP Paribas (yet another too-big-to-fail bailout company), they still charge you 3% of your own money to get it out of the account. If you have a Credit Union, you may be able to do better. But you already got the basic rule: Use a bank-owned and branded ATM, not Travelex or any other shiny, attractive object.

https://www.ricksteves.com/travel-tips/money

Also, if the ATM asks if you want to be charged in your home currency (USD, CAD, or whatever it may be) -- just say no!

This is DCC or Dynamic Currency Conversion which allows the ATM owner to use whatever rate they want to pre convert the transaction. That rate can be as much as 15% over what the processing network will charge. And on top of that, your bank will still charge you all the foreign transaction fees you would pay on the transaction anyway.

Your transaction will still show up on your statement in your home currency anyway as the processing network converts the transaction so your card issuer doesn't have to do any other than approve or deny the transaction.

The truth is that which card you use to withdraw funds is far, far more important than which bank ATM you choose to withdraw from.

Debit Cards: These take funds directly from a checking account. Two possible fees: First, An ATM fee charged by either the bank in Europe, your bank in US or both. Second, A foreign transaction fee. The possibility for these exists with every withdrawal you make. Some people will still pay these fees, but take out larger amounts less frequently.
You need to find out what your particular bank charges and know what the policy is for your card.

People often seek out a card from a bank or institution that minimizes or eliminates these fees for travel. I use Charles Schwab Investor Checking. No ATM fees ever worldwide and no foreign transaction fees either. There are other good cards out there as well.

Credit Cards: Take the fees that could be charged for Debit Cards and add a Cash Advance fee and interest charged from the moment of withdrawal to the costs.

If you plan on traveling beyond just this one trip, you may want to explore your options and open an account at a facility that minimizes or eliminates fees. The first step is to find out what your bank charges.

The only bank ATM I have seen in CDG is HSBC Bank, based out of London & NY I believe, located in the center of Terminal 2 across from the Sheraton Hotel. They have a bank & ATM. Travelex ATM's seem to have contracts with airports throughout Europe, you will see many of their ATMs in CDG.

I agree with the previous poster. Most ATMs at CDG are run by Travelex. If you want a bank ATM, go the top level above the train station in Terminal 2, where there is an HSBC bank and ATM. Otherwise, use the Travelex ATMs, but be careful to decline seeing your "transaction" in dollars. Always choose the local currency--in this case euros.