Prepaid SIM card for Paris - to be used for local calls with no data access required

At CDG, "Relay" shops sell SIM cards. Rick's guidebook suggests that Lebara and Lycamobile are economical options for crossing borders. There are also many shops in the city, some operated by a phone carrier, such as Orange. Staff should know what is right for your type of phone.

You might check out the Orange Holiday pre-paid Mobicarte system.
For 40 EU, you have ample minutes of talk and text, and can top up if needed.

I wouldn't buy this online, but print the webpage and bring it to an Orange boutique in Paris. This will avoid a lot of confusion, and you'll get exactly what you want.

The salesperson will unlock your phone and make sure everything works before you leave. Try not to visit the store when it first opens and at lunchtime, when you won't get the best service.
http://sites.orange.fr/shop/forfaits_mobiles/options/fiches/mobicarte_holiday.html

I don't believe there's an Orange boutique in the airport, but you can find their locations on this website: http://agence.orange.fr/

One in tbe city, I popped into the first tabac I came to, bought a 5€ Lebara SIM card and some top off time. Back at my apartment, I followed the directions to get an English speaking customer service rep and had the card activated in about five minutes. Very easy.

When we were in Paris last Fall (Sept 2015), staying in the Luxembourg Gardens area, we could not find a vendor willing or able to sell us a local SIM card for our unlocked GSM phone. We tried tabac's, souvenir shops, a department store and two mobile phone stores. In past years, buying a local SIM card would not have been a problem, but before we visited Paris last September, government regulations requiring online registration to purchase SIM cards (to combat terrorism) were so time-consuming that the vendors we tried were no longer selling them. Is there any reason why that has changed, or were we just unlucky in the vendors we tried?

You were not unlucky. Paperwork has increased tremendously due to the high security alert. That's why you must provide your actual passport and a local address when applying for a SIM card.

At first glance the Orange Holiday plan looked perfect until I noticed the fine print - it's only valid for 14 days; we require a plan for about 28 days and the OP needs coverage for 2 months. Like mobile plans everywhere, the devil is in the details and they never make it easy. Le sigh.