I don’t trust cell phones in foreign countries at all. When I was in Europe last summer (France, Belgium, Germany, Holland, and the Czech Republic), my family called AT&T to ensure that we would be able to use our phones once we were abroad. Being assured that we would and having worked out an international plan, we went and found that our phones were entirely useless. My phone never even updated to the correct time zone. Once we got back to the States, AT&T couldn’t explain why our phones hadn’t worked either. Best of luck, though! Have fun in France :D