I had a wonderful stay at Andre's studio. It is in a perfect location, easy walking distance to many sightseeing spots and super quick access to the metro that will get you anywhere you want to go. Also, it is perfect for any traveller who wants to experience Marais nightlife, have plenty of fun, and not have to worry about a long trek home.
The studio itself is very comfortable, private and cozy. The espresso machine is a really nice touch, the decor lovely, and plenty of dishes/fridge room/etc. There's not a stove or hot plate though, only a microwave/convection oven, so don't plan on extensive cooking. While it is small, it works great. It's not like you are going to Paris to hang out and host dinner parties in your apartment, right?
While it was perfect for me, I do want to mention that the bathroom is truly tiny. It worked well for me, but I am 5'6", and a fairly small guy in general. I could see that you could be uncomfortable if you are very tall and/or a bigger-bodied person. But if you are a pocket-gay, you'll be just fine.
So book his flat, it's really great!!