The flat is great, the sofa and beds are comfortable and it is a nice apartment to come back to after a day out at museums. We were 3 people and there is plenty of space. to stretch out on the sofas and hang out. The area is great, lots of restaurants and lively. The bedrooms however are very quiet and located on the back (not on the street) so you are not disturbed at night which is a real plus. Although the cleaning crew were still cleaning when we arrived, they did a great job and were very quick.
Guillaume is a great host, very responsive and pro-active. The kitchen is very minimally stocked (only one coffee mug) and Guillaume quickly brought us new coffee/tea mugs, espresso cups and a kettle.
The one thing to note is that the flat is on the third floor with no elevator. However, this did not bother us and thought the flat was worth it (and a good way to get in shape :-)
We would definitely book Guillaume's flat again.