Rinse the rabbit and pat dry. Peel the garlic and finely chop. Peel the onions and chop. Rinse the celery and finely slice. Rinse the tomatoes, blanch, peel and dice.
Heat 4 tablespoons oil in a roasting pan and sear the rabbit pieces until golden brown on all sides. Add the onion and garlic and sauté briefly. Deglaze with the wine then add the tomatoes, celery and peppercorns. Season with salt and then transfer to a preheated oven (180°C) (approximately 350°F) to braise for 50 minutes. Add the sugar and season with nutmeg and salt. Serve garnished with parsley and toast or crostini, if desired.