I visited Paris about ten or more years ago, and even back then the problem was obvious and in your face the whole time. The only happy memory I have is the Louvre, not even the Eiffel tower could somehow change the fact that I did get robbed.
They took my money and password, it was a nightmare and a challenge to get back home. I know this could have happened anywhere, but I traveled all across Europe, and it only happened in Paris.
From all the cities that I've visited Milan and Paris are definitely the worst regarding poverty and garbage lying around. I can only imagine how they look now.