They tweeted and took responsibility themselves. They claimed it. Do we need more evidence? Additionally, looking at the first reports it's predictable because (1) They were using bombs (2) And Kalashnikovs. Is there any other terrorist group that does attacks in France and uses this as frequently? I'm pretty sure other terrorist groups use Kalashnikov rifles, but in Paris it's not hard to make a rational guess. We don't need 100% proof for it.
Whoever fights monsters should see to it that in the process he does not become a monster. And if you gaze long enough into an abyss, the abyss will gaze back into you
