Actually, two of the nine Paris attackers were (probably) from Syria and had come as refugees, as they were registered with fingerprints in Greece.
A few of the others were French and were known to be in Syria, but how they came back to EU is apparently not known (could be with help from people smugglers, avoiding any registration at borders, because some of them were on wanted lists).
So three of them probably came as refugees. One of those has been identified and it turns out he was actually French, but you still assume the two unidentified ones were "real" refugees, rather than other French terrorists who had fought with IS and were trying the same trick?
I can't really say whether they are "real" refugees or not.
The point is more that border checks have ceased to exist.
Schengen area doesn't actually even try to verify who comes in, and that enables also movement of jihadists - even if they are only a few among thousands and thousands, but the few can avoid border controls.
