The most popular regions in France for British, American and other english-speaking communities are the Dordogne, Languedoc-Roussillon, Provence, Brittany and Normandy.

Paris also has a strong english-speaking community, made up mainly of Americans and English residents.
Tourists also play a big role, even if only seasonal.
One thing is certain, you can always find other english speaking people not far from where you live. I would recommend you check out our forum.