WiFi in France
From my experience - if you want open and useful public WiFi, find a McDonald's or a Buffalo Grill. The ones I have visited offer open WiFi that will let you connect simply by clicking the "I accept the terms" button and they'll (usually, not always) permit VPN.
Avoid KFC. Any attempt to access an https site will throw weird certificates at you. I'm sure there's a canned excuse there, but basically it is a MITM that utterly compromises any semblance of security. VPN is blocked, as is, well, pretty much everything.
More or less ALL Liveboxes of the v2 or later have the ability to act as a hotspot. The basis of how this works is that in order to have the right to connect to hotspots, you must provide a hotspot yourself. As a subscriber, you can sign in (provided you, yourself, provide a hotspot). Other networks? I think the hassles with the credits and such are so that if you email whitehouse.gov with a death threat to Obama, the telco can say "yeah, it was him wot did it", although given his approval ratings, maybe the Democrats would actually want somebody to conveniently deal with the issue. ;-) From some brief tests, the public AP provides a completely different IP address. It appears to be segregated from the home AP traffic (though, both use the same frequency). I have not conducted any tests on speed and quality of service. Orange assure me that public AP use won't impact my internet use, which I find hard to believe given that it is a 2mbit line, so anything over maybe 20-30K/sec when I'm downloading will be noticed. I have no problem with providing a public AP. I can barely receive WiFi in the next room because of the metre-plus-wide (!) stone walls, and the neighbours are, like, a mile away. The road is private and comes here only. So, hey, it's an access point for the bunnies and owls.
That said, my Livebox runs at 2mbit down, about 700kbit up. If I walk outside and stand in the middle of a muddy field and wait for my phone to sync to 3G+, the result on SpeedTest is approx. 2.5mbit both ways. Well, maybe only one way at a time, but it can outpace the wired network however you look at it. EDGE, on the other hand, is supposed to run at an exciting 17K/sec (ish), but I don't know if my phone is crappy or if Orange is crappy, because when my phone reverts to EDGE, it frequently can't handle any sort of transmission unless I can practically see the mobile tower (and by then it will have kicked up to 3G+). Go figure.
Anyway, this "you must be a public AP to have the right to use public APs" coupled with slipping this into a firmware update a year or two back and switching it on by default....this might explain why there are so many access points. I've seen Free and Neuf boxes offering logins to their subscribers upon connecting to them, so perhaps those companies do the same sort of thing?
Just looked at the login page for my public AP - you can buy a WiFi pass if you are a non-subscriber, and this might be useful to some - BT Openzone customers can now use French Orange public APs - you need your Openzone username and password (same as in the UK). I've dropped a screenshot here (imgur).