We're talking about two different Suds here. Sud or Sud Ouest (I think it may have been Sud 7eme at one point) was on rue de Grenelle near rue Cler and had decent Mediteranean food. It was not fine dining but they did pretty well at what they offered. This place closed a year or two ago (as did its sister location near La Muette in the 16th), and I know nothing about the restaurant that opened in the Grenelle space.

Au Petit Sud Ouest is nearby, located on Avenue de la Bourdonnais. It serves traditional French southwest cuisine such as fois gras and other goose and duck products. I haven't been there in a long time but I think they are still open.