Olivier's place was exactly as advertised - centrally located, wonderfully equipped, cosy, spacious.
At first the communication was a bit slower than I'm used to on airbnb (probably because of the language barrier), but we ultimately got all the neccessary information in due time. When we encountered an actual problem (the water heater turned off), Olivier's son immediately called and explained everything, which was very helpful.
The appartment is located just meters from St Michel's square and its basilica; the square is lively and the street very active, with all the main sights in walking distance. There are bars, shops and restaurants nearby. Capucins market is only a couple 100 meters away - I suggest visiting on a Sunday.
The appartment is spacious, cosy and stylishly equipped. We were a party of 6 and had more than enough space (2 decently sized beds + 1 retractable sofa with more than enough sleeping space). It has all the amenities one might need, including bed linen, towels etc.
Self check-in was really easy. Olivier let us leave our bags in even after our check-out time, because we had a relatively late flight which only added to the great hospitality.
Would definitely recommend to all future travellers.