Cell Phone Use in France

Your’re likely referencing the GSM voice frequencies of 850/1900 MHz used in N American and the 900/1800 MHz frequencies used in France/the EU. Most phones now have capability of all four voice frequencies.

For data above 2G speeds, which use the above frequencies, things get more complex as a variety of frequencies are used. Most US phones will receive at least one of the standard EU data frequencies, but overall data coverage will unlikely be as comprehensive using a US phone in Europe as it would be for those using EU phones. Of the 4 primary mobile phone providers in France; Orange, FREE, Bouygues, or SFR, each has a data plan with SIM that would likely work for you.

if your phone is a modern one, as Tocard says, it will probably limp along.

If, on the other hand, yours is a quite old one with only two frequencies and they are the wrong frequencies having a different SIM won't do any good - the phone still won't work.

What age, model, and brand of phone do you have?

I am currently using the French Orange Holiday pre-paid card. Like others have said most of the newer devices are world phones and will work throughout Europe. If your phone is more than 2 or 3 generations old you will want to check if it is considered a world phone.

So far I have been very happy with the Orange pre-paid card. I have had service 95% of the time (Denmark, Germany, Swiss Alps, Italy, Spain & of course France), the only issue being on the TGV from Barcelona to Paris. There were long sections in Spain that had spotty coverage, but the TGV had wifi. Reloading is also quite easy if you need more than 14 days. There is an English language web page that accepts American credit cards.

I have a Samsung Galaxy Sky. I got it in 2017. It's 4G if that matters? I called Straight talk and they told me the phone is unlocked so I believe it should work. I'm not a tech guy so the ins and outs of things like this are over my head!

if you're with Straight Talk, they're not a provider they are a reseller. So you need to find out their specific plans for use in Europe, it could be quite pricey. You should also find out which carrier they are reselling to you.

So then, you either buy a local SIM card when you get there and stick it in your phone hoping it works, or you buy a cheap unlocked world phone and buy a SIM card either when you get there or in advance on the internets.

Your phone seems to have some of the bands required in France, just not all of them. The 900 band is fairly common, which you do have, so that is good. However I'm unsure what type of experience you will encounter with this device, depending on where you are you may have perfect service but some locations may be spotty. I'm currently using my US S20 5G without any issues, but my device has access to several more bands.

Your phone:
https://www.pdevice.com/product/samsung-galaxy-sky-sm-s320-specs/amp/

List of bands used by country:
https://m.gsmarena.com/network-bands.php3?sCountry=France

I will just say be careful. We picked up local SIM cards for our phones when we were in Italy in 2019 and my IG and Facebook were almost instantly hacked. We are traveling in 2 weeks to France and this time we will be using our T-Mobile plan which includes international data. It's a lower speed but enough to get us map directions (which I will also download just in case) and then use wi-fi in our hotels and AirBnBs. International texting is included in our plan so we can keep in touch with family and our cat-sitter at home, however calling is not so we'll be judicious about that. So bottom line: whether or not to get a SIM card depends on what you need the phone for and how often you think you'll use it.

This is discussed quite extensively on the technology forum. The most common answer is Whatsapp and WiFi. Another option as noted is changing over to T Mobile before the trip.