Prepare the meat. Cut each type of meat into bite-sized cubes, about ¾ inch (2 cm) on each side. Keep the different meats in separate containers and refrigerate until you're ready to serve.
Prepare the sauces. If you're making homemade dipping sauces, prepare them ahead of time and keep them refrigerated in small bowls until you're ready to eat.
Make the red wine broth. Peel and finely chop the garlic. Peel the onion and thinly slice it. Cut the brisket into small pieces, similar to bacon lardons.Heat a drizzle of oil in a large saucepan and cook the brisket over medium heat for a few minutes, until lightly browned. Add the sliced onion and cook for a few more minutes until softened and golden. Add the garlic and bouquet garni, stir well, then pour in the red wine and broth.Bring the mixture to a boil. As soon as it starts to simmer, reduce the heat and let the broth simmer uncovered for 15 to 20 minutes. This gives the wine and aromatics time to develop a rich, flavorful broth. Heat the fondue broth. When you're ready to eat, carefully transfer the hot broth to your fondue pot and heat it again so it stays gently simmering at the table. Cook the meat at the table. Skewer a piece of meat with your fondue fork and dip it into the simmering broth. Cook the beef for about 1 to 2 minutes, or 2 to 3 minutes for chicken, veal, or pork, depending on how well done you like it. Adjust the cooking time as needed according to the size of the pieces.
Serve and enjoy! Serve the cooked meat with your favorite dipping sauces and plenty of vegetables on the side. Then let everyone cook their own meat and dig in!