Stayed at Le Relais du Louvre just one night for work in December 2011. It is in a prime location near the Louvre, not too far from the Pont Neuf metro station. But being off the main street means it is quiet at night and you'll still get a good sleep.
I took a walk around the area that night: to the Louvre, across the Pont des Arts, to the Notre Dame, etc. It is a very lovely location in Paris, much better than when I've stayed near Gare du Nord thinking I should stay close to the station for my Eurostar trip. It is worth the small metro trip towards the Seine and stay near there instead, much nicer!
The staff were lovely, certainly nothing to complain about there. They were helpful when I asked them questions, but in general I didn't need much since it was just a quick trip for work not several days holiday where I'd want to see the sights. They let me leave my bags on the second day, and use their bathroom to change when I got back, so I thought they were very accommodating -though other people may expect this from any hotel.
The room was small but most hotels in Paris are, especially in this price range. I got a good enough sleep so I was happy with it.
Little disappointed with the breakfast, especially with how much it cost - I would have expected more for that price. In hindsight I should have just bought a couple of croissants and a juice from a nearby cafe, it would have cost me less and been the same breakfast and I've enjoyed it more than sitting in my room at the small desk. Never mind, we live and learn.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC