Season the salmon well on both sides with lemon juice, salt and pepper and place in a small baking dish. Fry the onion cubes and the garlic with a little olive oil in the frying pan until translucent. Add the diced paprika, the cocktail tomatoes, the zucchini, 2 tablespoons of balsamic vinegar, 1 tablespoon of creme fraiche and the basil and sauté briefly. Season to taste with salt, pepper and oregano.
Put the vegetables over the fish in the baking dish. It is best to choose a small baking dish so that the fish is well covered with the vegetables. Cut the mozzarella into 8 slices and spread over the vegetables.
Put the whole thing in the oven and bake at around 180 ° C (top and bottom heat) for 25-30 minutes.