Yes, there are raw materials for jihadi attacks in French suburbs which can be no-go zones for non-Moslems or even French agencies.
But like criminals, you need both motive and opportunity to attack. Without outside help, much of the raw materials of jihad will simply be angry without resorting to murder, or their violence won't be terribly focused or lethal.
The Charlie Hebdo attackers had outside help:
Yemen’s Al Qaeda branch claimed responsibility Wednesday for the deadly assault on the French satirical magazine Charlie Hebdo, raising fears about the foreign training and financing of terror plots by self-directed European jihadists.
And the two Charlie attackers even went overseas to get training:
Both brothers who carried out the attack against satirical weekly Charlie Hebdo traveled to Yemen via Oman in 2011 and had weapons training in the deserts of Marib, where al Qaeda has a presence, two senior Yemeni sources said on Sunday.
There are other questions, too.
So fighting the jihadis "over there" may or may not mean we don't have to fight them "over here" (whether that means our "here" or France's), but it will mean that the fight over here will be less often and less lethal for our side.