Hollande said in his statement to the press that “we know who they are”.
Implying strongly that ‘police’ were, with some specificity, aware of this threat ahead of time.
I suspect that the French intelligence agencies have good info on their domestic terrorists but not on the new ‘refugee’ terrorists.
I, or the TV translator, may have misunderstood Hollande.
According to a translation he DID NOT say that:
http://wtnh.com/2015/11/13/web-extra-french-president-hollandes-statement-on-paris-attacks/