02Combine the mustard, crushed garlic (mashing it into the mustard with a fork), vinegar and olive oil. Season to taste with salt and pepper and mix well. Remove the garlic cloves and pour the mixture over the beans while they are still warm. Add the tomatoes, toss and set aside.03Meanwhile, trim the outer leaves from the artichokes. Cut off the stalks and slice off the tops, two-thirds down horizontally. Squeeze the lemon half into a bowl of cold water large enough to hold the artichokes. Cut the artichokes into thin slices vertically. Add them to the water as you trim them, to stop them from turning brown.04Heat oil in a skillet. Dry the artichoke slices in a salad spinner or with a kitchen towel. Add the artichokes and saute, turning from time to time until golden. Drain on paper towels.05Cook the shrimp. Bring the wine, stock, bouquet garni, onion and salt and pepper to boil. Add the shrimp and cook for one to two minutes. Do not overcook them or they will be mushy. Cool, peel and chop them in half-inch pieces. Add to the beans and toss. Correct seasoning.06To serve, place the mixture in a shallow dish and arrange the artichokes in a circle around the edges. Sprinkle with chives.