Sort the dried beans to remove any pebble or impurity; wash them thoroughly in running water.
Place beans in a large bowl; cover beans with water, 4 inches above the beans; cover bowl with plate and let beans soak 14 hours.
In a pot, bring 4 cups of water to a boil; simmer the salt pork for 10 minutes; drain.
Drain the rehydrated beans and throw away the water; place beans in a large cooking vessel; add the salt pork, halved onion, celery, 4 cloves of garlic, bay leaves, and thyme to the beans; add water up to two inches above the beans.
Bring the beans to a boil and simmer, covered, for an hour.
Preheat the oven at 375 degrees Fahrenheit.
While the beans are cooking, put the duck confit in a bain-marie to melt away the duck fat; once fat has melted away; set the duck legs aside removing as much fat as possible; set aside the fat.
In a skillet, use 1 tablespoon of the duck fat to cook the Toulouse sausages on medium heat, until both sides are golden brown, about 10 minutes; set aside.
After the beans have cooked for an hour, discard the vegetables, set the pork aside, and drain the beans but keep the cooking broth; set both beans and broth aside.
In a large cooking vessel that can go in the oven, use 1 tablespoon of the duck fat and cook the diced onion and minced garlic on medium heat until the onions are tender and translucent, about 5 minutes; sprinkle the flour over the onion and garlic mixture and mix until incorporated; add the white wine and the bean cooking broth to the onion mixture and bring to a boil.
Prick the Toulouse sausage with a fork and add to the pot; add the Rosette de Lyon chunks, the duck legs and the cooked pork ribs to the pot; then add the carrots and parsley; finally cover all ingredients with the beans and tomatoes.
Put the cooking vessel into the oven and bake uncovered for 3 hours.
Season the cassoulet to taste, cover the pot and let cool to room temperature; store the covered cassoulet in the refrigerator for at least 12 hours.
Cassoulet is best served reheated. Reheat in the oven at 350 degrees Farenheit for an hour then serve.