Preheat the oven to 400°F. Line a baking sheet with a silicone baking mat or parchment paper.
Use a fork to poke several holes in each potato. Bake the potatoes on the baking sheet until tender, about 45 minutes.
Meanwhile, heat a large skillet over medium-high heat. Add the ground beef, bell pepper, and onion. Cook for 8 to 10 minutes, until the beef is cooked through, breaking up the beef with your spoon.
Reduce the heat to medium, and add the tomato sauce, tomato paste, Worcestershire sauce, chili powder, and black pepper. Simmer for 3 to 5 minutes, until thickened.
Slice off a small portion from the top of each potato. Use a small spoon to scoop out some of the potato flesh. Spoon the Sloppy Joe mixture into the potatoes, top with the cheese and Crème Fraîche, and garnish with chives.