The Hoxton, Paris

Still a great place to work from. No one bothers if you stay for a long time and it's a large area. Only downside is that they have constant music playing and from 17h on they increase the volume a lot.

It's a huge lobby of a hotel that's built to be used as a co-working space for people who work on the go. You don't have to be a hotel guest to use it, which is great. Best practice is definitely to at least buy a cup of coffee, however.