Not any capital city - Brussels specifically. There was a lockdown of nearly a week after the Paris attacks. People were really bracing for an attack, in a way that London, Berlin, Amsterdam, Vienna, etc. weren't.
My point was that it is really easy to say that any big city will have a terrorist attack. So it's never if, but always when. Yet with all the surveillance and lockdowns they have, they didn't see this coming, which was the point of the parent, that more surveillance is not going to solve anything.