I live in France. Conventional, boring France, where everyone wears navy blue and eats cheese and watches cycling. The idea of a civil war breaking out here is absurd.
France is the least tense place I've lived. I grew up in London, where I felt the difficulties of multiculturalism much more acutely than I do here.
In NYC, cultural differences between communities felt even more profound (I didn't see very many mixed-race kids the way I do in Europe, for example).
I lived in Mexico City and Buenos Aires, in both of which I felt political tensions and anti-government sentiment to be much stronger than they are here.
I lived in Madrid. Multiculturalism wasn't the issue there, but economics was a divisive topic.
I lived in Moscow, where race relations were pretty strained, and the political leadership was... well, we all know about Putin. But... in France? In France I see little muslim kids holding hands with little christian kids with their white French nannies (government childcare provision). I see French people buying olives in the North-African shops, and Arabs fixing Jewish people's cars. Yes, there have been extremist-Islamic terrorist attacks. But there have been those all over the west. London had terrorist attacks, and no-one is heralding another English civil war. New York had terrorist attacks. I'm not sure why someone would think France is about to erupt into Civil War. Maybe it's because the French press talks about race a lot. That's more a sign of an open press than it is of imminent war, though.