I just got an Orange Holiday SIM for my iPhone -- bought it on Amazon & it was delivered to my home 2 days later. It gives me a French phone number, 20GB of data, and 120 minutes, and 1000 text messages for 2 weeks. I can "top up" if I need more. Since we travel about every 2 years, it is worth the money to "top up" the minimum amount every 6 months to keep the phone number active so we can use it on our next trip.
There are other SIM options with other providers, but Orange is France's largest network.
If your phone cannot work on the French systems, check with your friends to see if they have an old phone they aren't using (I seem to have several) that you could borrow for your trip & just pop the SIM card out & replace it with a French one.
Last trip, I didn't use any data. Kept my phone on airplane mode unless I was on wifi. I used Facebook Messenger to call my daughter back in the US. My phone is also enabled for wifi calling so I could do that as well if I needed to call someone NOT on my FB friends list. That might be an option for you as well. You could get a mobile hot-spot and use the wifi from it to make calls.
Good luck & have a great trip!