Very lovely apartment. As described, it is small, but charming. Some mentioned that you can hear the noise of the subway: that's true, but it's not a strong noise, stops early, and it my case i even liked it, it helped me to sleep :)
No internet in the flat, pay attention to the description (was not an issue in my case, but it's important to be aware of it).
Honestly, it's Paris, and the studio is extremely well located. For the price, you might not find a better place