We had a comfortable, problem-free stay here. The location is unbeatable: you can reach pretty much anywhere you’d want to go in Paris in under 30 minutes on foot, and of course all the restaurants, shops, bars and museums of the Marais are on the doorstep.
The apartment itself is spotlessly clean and bright, with huge windows and high ceilings. The bed on the mezzanine is extremely comfortable. The property is reasonably well equipped, with a plentiful supply of towels and linen, a great modern bathroom, and an efficient washer/dryer for longer stays. It also has super fast internet and TV that worked seamlessly throughout our 3 weeks. The host Thierry was brilliantly responsive and answered all my queries within the hour; self check in and check out were both extremely easy.
Be advised that there are lots of other Airbnb / short term lets in the building, so there’s the potential for noise. This was only a real problem on one night (out of 21!) but there’ll be people coming and going in the central courtyard till quite late most evenings. This doesn’t detract much from the advantages of the location, and we had a great time.