Make the vinaigrette: In a small bowl, whisk together Dijon mustard and white wine vinegar, then slowly whisk in olive oil in a thin stream. Blend the mixture until smooth.
Boil potatoes in water with garlic sausage until the potatoes are slightly crunchy at the center. While the potatoes are cooking, boil chicken stock and white wine until it is reduced to a scant 1/2 cup. Remove potatoes from water, drain, and while they are still warm, cut them into 1/8-inch- thick slices. Arrange slices on a platter, season with salt and pepper, pour the reduction over the potatoes, then turn the potatoes over and repeat the process. Allow the potatoes to absorb the reduction for 5 minutes. Cut the garlic sausage into thin rounds, and then alternate slices of potato with slices of garlic sausage for presentation.
For the garnish: Combine tarragon, chives, parsley and Swiss cheese bits. Sprinkle this on the potatoes and sausage first, then drizzle the vinaigrette on top.
For an alternate presentation, the potatoes and sausage can also be placed in a bowl on top of greens, then topped with the garnish and the vinaigrette.
Wine: A very young Beaujolais Village from Georges DuBoeuf