The French intelligence and counter terrorism units are either not doing their best or these terrorist are getting much better at covering their tracks.
Should have been picked up?
You think secret services are omnipotent? That they can get a whiff of every conspiracy.
>The French intelligence and counter terrorism units are either dangerously incompetent or these terrorist are getting much better at covering their tracks.
Or, there is way, way more of them. Currently, thousands of migrants are entering Germany each day. No one is checking them, fingerprinting them, taking their photos or running those against databases.
You can find useful idiots decrying such treatment: http://www.independent.co.uk/news/world/europe/refugee-crisi...
Doing so would require a lot of coercion, so no one is doing that.
My guess is that the Daeshi idiots slipped in a martyr cell or two. These guys got weapons from black market and executed a well-planned attack.