I've visited Paris often thanks to Nomador.
I've used Nomador several times. Always an easy and happy experience, with the exception of once when the homeowner cut short my catsitting suddenly which caused a lot of inconvenience, and I was unable to leave a negative review according to Nomador' rules. It's best to have a plan b. But as for the way the site is run, in general, it's been great and very useful.