It's been a couple years, but when I was in Paris last, the area around the Eifel Tower was swarmed with pickpockets, people trying to sign you up for scammy petitions, and furtive junk souvenir sellers. Combined with the heavy paramilitary police presence, swaggering around with submachineguns, it wasn't very inviting.
Out of cities I've been, Paris was far and away the worst. I don't see this in Berlin, or Amsterdam, or Boston, or Washington. It's the kind of scene I'd expect in the Caribbean.