Let's face it. Many buildings are empty.
Rats always come back to the same places. When they once have had established a nest, they will try to repopulate it. Each population you kill, without erasing the nest, will attract another one to use the nest.
Pulling down the empty buildings won't help. They then just use the remainings or empty site.
Instead, the buildings and spaces need to find new inhabitants. They need to be populated by others taking the space of those acting sociologically like rats away.
Franc has a strong Public Garden tradition. Paris is off the Tourist Luxurious spots a prime example of that and Frenchmen will complain first loudly about a running down Public Garden before anything else going wrong in town.
Pull out all windows, doors and everything that can rot. Strip the buildings down to the rather solid concrete structure and turn them into vertical gardens. Eventually, Paris will copy in a big klimbim happening that creation creating another landmark like the Centre Pompidu or Opera.
They can't copy the harbour... that they should and will.
