Buying a French SIM card

Chances are in the baggage claim area you will see a stand with Orange sim cards.

We had very bad luck with buying a sim card at the airport in CDG. We were given very little instructions and tried to find a store in the city of Paris who could help us with the instructions. We finally just gave up and after doing all we could to get some kind of response from the company just contacted our credit card company and had the charge removed. The people who sold us the card never responded to our allegations so our money was credited back to our account. We got the Orange sim card from a store on the Champs-Elyesees. It's a jungle out there for us in our late 70's to get sim cards. Maybe it will work better for you. I believe we were told on this web site that it was easy to get it at CDG. "Easy for you! Difficult for me!" Good luck to you.

Haven't done it, but based on what some others have posted I would get a SIM at a store near my hotel so I could go back to the same person if something went wrong. LOTS of places in Paris.

We bought an Orange card at CDG (Terminal 1) at the tabac stand just beyond baggage claim, a few feet from the Info Desk. It was our first use of a SIM. We are in our early 70s and not at all tech-savvy. The included instructions in English were clear and simple, and we had it working in minutes. That said, we waited to do this until we were checked into a hotel, and could open and study the tiny card and instructions in a relaxed atmosphere. Before leaving for Paris, locate the SIM tray on your phone and experiment with getting it open and closed (a small/medium paperclip will do the job). Have some sort of receptacle for your original SIM (e.g. small ziplock bag) for safekeeping until you swap out the cards at the end of your trip.

First, make sure your phones are unlocked. At CDG you can get SIM cards at any of the many Relay shops.

I'd go to your friendly neighborhood Orange Boutique, where there won't be any crowds.
This is what you need:
boutique.orange.fr/mobile/carte-prepayee-orange-holiday-eng
It's $ 39.95 - I'd suggest printing out the page you want so the salesclerk won't be confused.
The agents will unlock your SIM cards. You will need your actual passports.
Don't go when lunch is planned - about 1 to 2 PM, or around closing, either.

One time I bought an SFR SIM card at a small electronics shop near Republic Square. Another time I purchased an Orange Holiday card at one of their boutique stores near where I was staying. The wait was shorter at the electronics shop but the help was better at the boutique store (and they are much more likely to speak reasonably good English).

CDG has WiFi, so I felt like I didn't need to pick up a SIM card before I got downtown.

Make sure your phones aren't locked. Years ago I had an AT&T phone. It was like pulling teeth to get them to unlock the phone before a trip (either AT&T had intentionally not trained people to unlock phones, or they had trained them to say they couldn't do it). Since then I've only purchased unlocked phones and buy phone service separately.

I'm afraid we're on the negative side. We bought a SIM card in Chartres at a store where only the salesman spoke English and his was very limited. He assured me the phone was working as we left the store, but it wasn't. We had no reason to use it until we arrived at our next destination, when we found out the phone had no service.
The phone didn't work during our trip, despite help given by our hosts along the way. One kind hotel manager in Sarlat spent about half an hour on the phone with Orange and the phone still didn't work. On our next-to-last day in France, we chanced upon an Apple store in Paris. There the problem was fixed in minutes by an English-speaking Apple "genius".
I had read through the instructions (in French) and thought I understood that I had to enter a code to activate service, but I was reluctant to do so, since by then it would have been our 3rd or 4th attempt and I was afraid of being locked out (barred from any further attempts). Turns out this was the right solution but after a while we just got used to managing without the phone.
Surely, we deserve the lion's share of the blame, but my advice is to deal with someone who speaks English unless you are fluent in French. The fix here was pretty simple but neither we nor our hosts were able to make the phone work.

If you mostly need data not voice calling, consider buying a SIM from another country like the UK or the Netherlands that does not require you to be in country to register a SIM. That way, you can buy a SIM ahead of time and set it up in your phone before you leave for Europe. This is what I did last year when I bought a Dutch Vodofone SIM on eBay before using it in Slovenia, France, and Italy. You can find my thread about this on the technology forum.

The Dutch SIM may not be ideal if you wish to make phone calls to French phone numbers. It will still give you a Dutch phone number that Europeans can call you on - better for them than calling a US phone number. And incoming calls and texts are generally free on European SIMs anyway. If you are American, you can use Google Hangouts on your smartphone to make free calls home to the US, even to landlines.

If you print out the page(s) you want the manager will help you.