The French Media refuses to cover any of this, but large parts of Paris are heavily populated by African migrants (where France had several colonies). These men (and almost all are army-aged males) have no jobs, no hope, but it's better than being back in their homelands.
So 'underground media' fills the vacuum of truth and reports on how these things are happening -right now, not in some abstract future. Huge parts of the city are already gone, and the police (and army) can't keep the tourist areas safe forever.
Note: Yes, the originating video (not the video linked here) contains an ad at the end (linked at the link) for an unsavory group. That doesn't mean the images and facts are incorrect. It just means that unsavory groups are the only ones reporting without a filter.