Marc studio is great. Is extremely clean and very well doted. Has a big window and a fan which was great for the hot days of June.
It's very well located, close to metro, and also close to other great places like notre dame, luxembourg garden, etc.
Checking and checkout was smooth and without any problems, and even we didn't met Mark, we thought he was great communicating with us.
One advice is be ready for the 6 floors climb especially if you have heavy bags. It wasn't a problem for us though, but just a heads up.