Cut the peppers in half and remove the seeds.
Put the tuna, capers, pitted olives and diced feta cheese in a bowl and mix with the tomato juice. Season well with salt and pepper.
Place the bell pepper halves on a baking plech, fill with the filling and press it firmly into the pods. Sprinkle the Emmental cheese on top.
Bake the stuffed peppers in a preheated oven at 200 °C for about 10-15 minutes.