Mobile phones are be very handy for booking accommodation ahead or calling a taxi, as well as for keeping in touch with people at home.
For all emergency services, ring 18 or 112.
Access to the internet is no problem in France if you are carrying a smart phone or something similar – almost every bar, hotel and camping ground has free WiFi.
Until recently, you could often access the internet at offices of tourism, public libraries (médiathèques) or cybercafés, but now it is very difficult.
As for ourselves, we take iPhones, which can connect to the internet via WiFi. However, we do not use Global Roaming, so we cannot make phone calls (but are also not bothered by incoming calls).