Sprint High Speed Data in France

I have used Sprint's basic international plan in France twice, as recently as 2016 (and Switzerland in 2017). The free data plan was at 2G speeds and it worked just fine for me. The GPS for GoogleMaps, my Paris Metro app, and various other walking around town apps worked great. I would not see a need to pay extra for a faster data plan just for that.

Despite this, I did pay extra for the rental car's GPS option. It was well worth not having to fumble with the phone's map and instructions while trying to drive on strange French roads.

Sprint? Ugh. I was a sprint customer for 17 years before dumping them in moving on to a provider who cares about their customers.
2G ugh ugh Almost unusable!
Do yourself a favor and stop by an Orange shop when you get into France and buy the 14 day holiday plan for €40 which gives you 4G speed and 10 GB of data, 120min of calls in Europe and 1000 texts. I was lucky and I got 20 GB on mine. You can type it up anytime at a grocery store on online and then it’s good for up to six months.
Switch out your Sim card on your Phone.
https://boutique.orange.fr/mobile/carte-prepayee-orange-holiday-eng

@tqhabib, I'll look into that. Thank you! It may be complicated, though, because right now I actually lease my phone instead of owning it, which means that I can't swap out sim cards at this point. I might consider just buying a cheap phone for the 2.5 months I'm there. Any ideas whether that's possible?

2G is perfectly fine for normal data usage, especially when it's free. I speak from recent first-hand experience in France. The other guy is a first-time poster and is selling something.

The Orange Holiday Sim worked great for me in cities, remote rural areas and islands, in France and other European countries. 4G LTE, 10g data plus texts and calls to US, European roaming. €40 for 2 weeks.

But you need an unlocked phone. If your travel partner has an unlocked GSM smart phone that can act as a hot spot, they could install this Sim, and you could tether your phone. Or as you say, buy an unlocked cheap or reconditioned GSM smartphone before you leave.

Wait, I just saw that your trip is 2.5 months, only 10 days France. Where else are you going in Europe? A Vodaphone plan might be another option. vodaphone.nl

The other guy may be a first-time poster, but he's linked to a reputable and well-known product.

Indeed, though, one has to have an unlocked phone to buy a local SIM anywhere.

If the rest of your travels are in Europe, and you buy a French SIM, you can use the SIM anywhere in Europe. The EU broke down roaming barriers a couple of years ago (June 2016 to be exact), so a European card that's good in one country will work in any other European country.

I should clarify: though the original post was about a 10-day vacation, I'll actually be working in France all summer (with a couple of two-day trips to the Netherlands and Switzerland). I think that someone in our vacation party is planning to purchase the high-speed plan from Sprint, so we're covered during those first 10 days, but now I'm thinking about what I'll need for the rest of the summer. Depending on how much it would cost to buy out my phone lease, I might just purchase a cheap phone in France. I don't need anything fancy, so I should have a few options.

You could always get a mobile wifi unit. We used Skyroam and it was perfect, especially as it covers up to 5 devices at a time.