My husband and I stayed in Olivier's flat with our 1.5 year old son.
Olivier was a great host. He was very responsive to all my messages. He arranged for a crib for my son (he managed to buy one used from a friend who was moving, and I just paid him a small sum for it). He offered to lend us his bike (so that we could pay to rent one instead of 2). He sent us suggestions for things to do.
The elevator in the building is very very small (compared to north american standards), and we couldn't fit out stroller in it without folding the stroller up. This wasn't a problem for us, and didn't detract from our stay at all, but other travelers may find it helpful to know in advance.
Overall we had a great time staying at Olivier's place.