Going by price and location, I booked 3 nights at the Hotel des Grands Hommes. It was much nicer than I expected considering the 3-star rating. The room wasn't large, but it was very comfortable and I liked the elegant old-world style. Another plus was the free WiFi.
It's a bit outside the centre in the Latin Quarter, but it's easy enough to get around by metro. It's also very close to the Botanic Garden for a morning stroll.
I would stay here again - it's a good value by Paris standards and the staff really make you feel welcome.