Ate lunch at La Mere Germaine with group of restauranters back in January during a visit to the Southern Cote du Rhone. Very pleasant dining room and great service. As you can imagine, a very good wine list. Food was ok, but nothing out of the ordinary. We had a much better meal in the neighboring town of Vacqueyras. The name escapes me, but I will check my notes at home and repost.
Following up: We had a good experience at La Mere Germaine, but I can't say the food was stellar... or even above average. We did their seven course meal with wine pairings. The wines were excellent and actually made the meal worth it in itself. The only food item that stood out was the potato gratin... one of the best I've ever had.
We also ate at La Garbure in CDP. Don't bother. We were served frozen vegetables with our entree... need I say more.
food in CduP is very ordinary. I always suggest doing lunch as a picnic up at the Papal Palace ruins... the sandwich shop makes a very respectable Pain Bagnat, and you should definitely accompany it with a bottle of white CduP! then go back to Avignon for dinner, or up to Mondragon to Beaugraviere for great food.