On the other hand I would like to see this study that shows that increase in the level of education and occupation doesn't do much. I suspect the issue is more subtle: in that many immigrants coming from the former colonies of France don't really identify as French (even after a couple generations) and don't fully accept the so-called 'republican values'.
The fact that many of Portuguese origin are converting to radical Islam seems to me as a further symptom that the power of Jihadism actually stems from socio-economical marginalization.