This is sweet and simple. The shower may be cramped for some larger people, but you really can't beat this for the money. It's right next to Place de Monge and an easy walk to the Grande Mosque, the Latin Quarter, Pantheon, or Notre Dame. If you want to save a bit, the kitchen is serviceable, and there's a neat little patio out back. With the Murphy bed raised it's got plenty of space.
Also this guy needs to publish his food suggestions. Paris is a gourmand's paradise and Valentin has a great list of local spots for you to check out.