Technically speaking, those regions (which I mentioned above) are not colonies. Of course one could argue they are in all but name (and I would agree), but they have nothing to do with any case of terrorism on the mainland, which is what the above poster was saying.
As to the rest of your post I agree with your point, but those are not colonies (the OP was deleted since but it said that terrorism happens because France still has colonies, which is bullshit on many levels).
What even are you on about ?? We have no colonies left. There are a few French “enclaves” left out of the mainland, but they are isolated, forgotten about (in a bad way sadly, shit is tough there) and absolutely not a source of immigration.