I hazard a guess without knowing much at all that would support it, that the group of terrorist who did this were somehow connected to some sense of loyalty to that repugnant and inhumanly cruel Jihadi John, recently killed. IIRC, JJ was trained by Al Shabab or something like that, with connections to ISIS and AQ, in Somalia, basically the French speaking African theater of their tentacles. As they seem to me to have the same intent, the same cash flow, cross pollination of expertise, ideology, ISIS being the tip of the spear, the more plausibly deniable perhaps, and less controlled. It may be why it's been so hard to confront, either what we don't know, understand or it is eye wash or all three.
I have no doubt that everything that's great about France will make it through, ultimately. The West however seems caught in the middle of wars within wars with people who don't know how to make peace with each other or fight each other without dragging others into it their wars, ruthless, calculating and forever cowardly in their choice of victims.
