The strength of the Armagnac brandy and the sweetness of prunes complement the gamey flavor of the boar. As with most stews and ragouts, this stew benefits from being made a day in advance to allow the flavors to develop overnight. Be sure to skim any collected fat before reheating. You will find that there is much less fat rendered than with a pork or beef stew.
Combine prunes and Armagnac in a bowl. Let sit at least one hour at room temperature.
Heat 2 tablespoons olive oil over medium-high heat in a dutch oven or oven-proof pot with lid. Season the boar meat all over with salt and pepper. Saute in batches, without overcrowding, until brown on all sides. Transfer meat to a bowl.
Add bacon to dutch oven and saute until the fat renders. Add shallots, carrots and onion. Saute 5 minutes. Add garlic and saute, 1 minute. Return meat to the pot. Add prunes with the Armagnac, wine, bay leaves, bouquet garni, 1 teaspoon salt and 1 teaspoon black pepper. Bring to a boil, then reduce heat to a simmer. Cover pan and transfer to oven. Bake until meat is very tender, 2 to 3 hours.
Remove from oven and taste to check seasoning. Remove bay leaves and bouquet garni. Stew may be prepared up to 1 day in advance. Cool, cover and refrigerate. Warm over low heat or in a 300-degree oven before serving. Serve with mashed potatoes or polenta.