While we’re in France, we’ve being using a smart phone app called MapsWithMe. There’s a free version and one that costs around $5 which we use. It’s really good: first, you download the maps of your required countries or regions before you depart.
Then, you can access them WITHOUT having global roaming on – ie no access costs. It’s great to use when wandering around cities, and we’ve found it useful sometimes when our Sat Nav isn’t giving us the information we need.