In a large stockpot on high heat, cook the oxtail or bacon slightly.
Add the meat (beef or pork) and brown on all sides.
Add the onion and cook until translucent.
Add the leeks, carrots, turnips, celery, garlic, bouquet garni, black pepper, herbes de Provence.
Add enough water and white wine to cover the ingredients and bring to a boil.
Reduce the heat to simmer and cook partially covered for about 3 hours, until the meat is tender.
Skim foam off the surface occasionally.
Strain the vegetables from the meat and broth and set aside for later.
Return the meat and broth to the pot and bring to a simmer. Cook partially covered for another hour, add the potatoes after 30 minutes.
Remove the meat from the broth, discard the trussing strings and carve.
While carving, warm the vegetables in the broth for a few minutes until warm.
Serve the meat and vegetables along with some crusty bread.