You will not find a better location anywhere in Paris. Situated on the Isle St. Louis you can walk everywhere with ease. Walk out the door to the corner and you have an amazing view of Notre Dame being reborn from the fire. The Marais is a short walk away as is the Latin Quarter and the locations you don't want to walk to are easily reached by the Metro just five minutes away.
The only qualification I have is the size. It's very small. Beautifully appointed with everything you need but very small. My wife and I are average size (5'9") but even we had to be mindful of not bashing our head against low hanging beams in the bathroom. But if that doesn't bother you you are going to find a cozy, perfectly located apartment that allows you to explore Paris.