Christophe's apartment is located in (in my opinion) one of the nicest districts in Paris and is not far from anywhere. The communication was brilliant and the apartment easy to find. However, as has been previously mentioned there is a significant amount of mould on the bathroom ceiling, the bathroom door was quite difficult to close and there is a plug socket hanging off the wall in the bedroom.
There were no ceiling lights despite there being switches for them on the wall so we were reliant on one lamp in the bedroom although since it is summer that wasn't a problem.
We only used the apartment as a base for sleeping and showering for 4 nights. I think any longer and the above may have been a problem for us.