Actually finding free wifi in France can be quite difficult. In Paris, for example, almost every bar offers wifi but the vast majority require you to buy a voucher to access it. Unlike in the UK, the idea of almost universal free wifi doesn't seem to have caught on among bar owners (which is rather odd because Paris has free wifi available in all major parks and public buildings anyway!)
There's a restaurant/bar I use, opposite the Gare du Nord, precisely because it's the only one in the area with free wifi (and even that's time-limited). Everywhere else in the area wants me to pay for it :(