Buying SIM cards in France .

Map displays can be downloaded by either WiFi or GSM. GSM data service is provided by a SIM. WiFi operates independently of the SIM card.

Orange has several plans based upon your need. Mobicarte is an Orange option for those using mostly data. SFR, la Poste, Bouygues, among others, all sell similar plans.

Most phones allow you to download maps in advance and store them, saving on usage fees.

I've used Orange Holiday Card the last two trips (last one was last June). The card works for 14 days from the day it's activated, you can add time after the 14 days but you have to go to an Orange store (as opposed to online or at a Tabac). Adding ten euro for a handful of extra days is probably plenty. I think I last used Vodaphone in Spain four years ago.

The 50 euro Orange Holiday SIM comes with 10 GB data. I normally use it sparingly by switching off data and using WiFi whenever I can. When I'm navigating, I turn data off. I normally end up only using 2 GB of data in two weeks so I guess I could afford to use data more than I do.

On the road I've used Co Pilot as my GPS app. You download maps before your trip. I think you can download just the France map for free (I downloaded Ireland for free in May), downloading all of Western Europe costs $30. Once it's downloaded, it navigates without data. You really only need data when you search for a location. If you have a street address to navigate to, you don't need data for that.

I've used Google Maps as an alternate but I've found it's both a data and battery hog - so I avoid it. I use Google Maps primarily to search for a street address to plug into Co Pilot. I think Google Maps gives better search results. When driving with Google Maps, you can turn off the data. It will navigate fine unless you miss a turn. When that happens, Google Maps won't reroute you unless you give it data.

I've used SFR twice, once with good results the other with horrible results. Last trip (last June) SFR stopped selling SIMs at their boutique stores. They now only sell them at Tabacs. For me that put them off my list because I prefer to have the card in and working before I pay them, which makes it important to purchase the card at the boutique. The time my SIM didn't work, I bought it at a Tabac but it didn't work. I went twice to a boutique to solve the problem. They didn't get it working but didn't refund my money either, so I was out 30 euro with no service.