Combine boar, wine, onion, carrots, juniper, and bay leaves in a large bowl or bag. Marinate refrigerated at least 8 hours, ideally overnight.
Remove meat from the marinade, patting dry, and reserve the marinade.
Heat oil in a large pot over medium-high heat. Brown the boar in batches, 5–6 minutes per batch. Set aside.
Add the marinade vegetables to the pot and cook 5–6 minutes until softened.
Stir in tomato paste, then add the reserved marinade liquid and broth.
Return boar to the pot, bring to a simmer, and cover.
Braise 2 hours to 2 hours 30 minutes until fork-tender.
Season with salt and pepper and serve hot.