Actually, it was along the route from the Place de la Republique to the Place d'Italie, so 3rd, 4th, 5th, down to 13th. The city is not all aflame, this is in pretty avoidable areas. It is as if the post-Rodney King riots were extrapolated to mean the US was a no-go zone. That said, there are some very violent "casseurs" coming in from the suburban ghettos to capitalize on the chaos. They have nothing better to do because literally 50% of them are unemployed. The strict French labor laws essentially keep them on the dole, where idle hands are the devil's playground...
I was in the 4th and 5th on foot this evening..nothing. Nothing as far as the could see from just east of the Notre-Dame to the south. It was much more isolated then anyone imagines.