What is a "green district ?"?

Question

In Paris there are so-called "green districts." What exactly does this entail?

Answer 1

it's either ecological or safe

Answer 2

http://www.guardian.co.uk/environment/20...

Answer 3

Hookers that recycle condoms and lube, and conserve water by not showering in between clients.

You also save some "green" because these ladies cannot command much of a price.