Preheat oven to 450ºF (230ºC). Combine potatoes with 5 tablespoons vinaigrette and place them in an oven dish. Lower oven to 376ºF (190ºC) and bake potatoes until they are tender, stirring frequently. Remove potatoes from the oven and transfer them to a large bowl. Let potatoes cool slightly. Stir in 5 tablespoons vinaigrette and 1/3 of Roquefort cheese. Season with salt and pepper.
Cook green beans in boiling salted water until crisp tender. Drain and and rinse under cold water. Drain again and transfer to a bowl. Stir in 3 tablespoons cheese and 4 tablespoons vinaigrette and the chopped nuts. Season with salt and pepper.
Place potatoes in the center of a serving dish and place green beans around. Sprinkle with Roquefort Cheese.
Mix mustard and vinegar in bowl. Gradually whisk in oil. Stir in shallots and herbs. Season with salt and pepper.