Hard to believe. I knew to avoid St Denis, but I think I was through there on my way to and from the airport and I really was looking for squalor. I didn’t see any.
Probably the closest I was to the 19th was the 11th which is closer to the Seine. No squalor there either. I still wonder about your picture.
ML/NJ
It's not mine. Your question just made me curious. I did not find a clear provenance for that photo, therefore the "FWIW." It is usually sourced to "an anonymous Frenchman." It supposedly shows the effects of Muslim immigration on Paris. Maybe it shows exactly that, maybe not. You are right to be skeptical.