I stayed in Nikola's studio early in April for a week, and I really enjoyed it very much. The studio is very cosy and is really what you are looking for in Marais.
Nikolas is a great guy and he helped me a lot introducing me the studio, the neibourhood, and providing me tips for Paris. He also wait me in my late check in (~22.30).
I hope I will return soon and stay back in this lovely place!