My husband and I and 2 teenage children spent 5 nights in Guillaume's apartment in Paris. The position was fantastic. You step out the front door and everything that you want to see in Paris (except the Eiffel tower) is a short walk away. The apartment itself is well furnished and comfortable. Everything works well and is easy to use. My children didn't particularly like sharing the double sofa bed, but there was an extra mattress available so arguments were kept to a minimum.
The view was superb, exactly as advertised. And the hosts were very very helpful and addressed all out requests. Definitely ask Guillaume for advice on restaurants because there are lots of average 'touristy' restaurants in the area!
A wonderful apartment which made our stay in Paris even more enjoyable. Thanks Guillaume and Julie