Yep the three network have now added France to there “feel at home” countries so calls, text and data are just taken from your allowance as if using your phone in the uk - happy days 
They are becoming a really attractive option. If they would add Germany or Holland it would be the icing on the cake…
Think they have now, well maybe not but there are a fair few countries on the list.
My EE daylight robbery (er contract) is up in a couple, last time I commit to a phone contract, I will try 3 with unlimited data for amazon prime video.