We had a wonderful stay at Guillaumes apartment with our two kids (7 and 9 years) for two nights. The apartment was very clean and beautiful as descriped. Check-in and check-out was very easy. We did not meet Guillaume in person but the communication worked very well so we had no problems at all. We found everything we needed in the apartment. The kitchen is well equipped if you like to cook. The location is central so we walked most of the time to explore Paris. Also supermarkets, bakeries, cafés and restaurants are very close. We definitely recommend this appartment.
For those not afraid by a bit of sport (6th floor by stairs) as it was our case, Guillaume flat is fantastic. Location was perfect: it is really 50m from the closest metro station, and within 500m you have access to multiples one on many lines. Area is really great. The flat itself is very nice, lively and typically parisian (as french, i lived myself in Paris during 10 years... but this flat is much larger than any of those I lived in). Guillaume was very easy to contact and the week-end was a pleasure for my partner and me. I would definitly recommend Guillaume flat (if you are not afraid by stairs).