I highly recommend this place for location and value. It's in a great part of the city, just a short walk from three Metro stations, and not far from Notre Dame, the Louvre, and Musée d'Orsay. Perfect location for exploring the Left Bank and beyond.
The staff is very helpful. I tried my (beginner) French with the front desk staff, but they were very happy to switch to English. The housekeeping and foodservice staff did not speak much English, but it was never a problem
The Louisiane is a fun, sort of artsy place to stay. The corridors and carpets are a bit worn, but that seems to add to the historical appeal of the place. My room and bath were very clean, and the breakfast was outstanding.
To note, my room facing the street was very noisy in the evening. There are several cafes nearby, which are busy late into the evening, as you'd expect. I recommend earplugs and maybe eye shades. I used both and slept like a baby.