I've stayed at the Rive Gauche many, many times and it's a wonderful hotel with great rooms and friendly people. If you've never been to Paris, maybe it's worth it to stay in a much (MUCH) more expensive hotel such as Vendôme or Champs-Elysées. I've never stayed at either and don't plan to, because the Rive Gauche gives me everything I want in a hotel of Marriott quality.
I admit to being fluent in French (but everyone at this hotel speaks English, as do most youngish French people in Paris) and having lived in Paris for more than 2 years (not far from this hotel).
I can't comprehend -- except for business -- why ANYONE would stay at La Défense. It may be a fantastic hotel and it's on metro lines, but you can't walk there from here. From the Rive Gauche, you can walk all over Paris. You're not next to Notre-Dame or the Louvre but it's a short ride (Denfert-Rochereau or Place d'Italie being the best places for connections) or a better walk to any of these. It's Paris! Enjoy!