For the sauce, clean the peppers and cut into small cubes. Sauté paprika, crushed garlic and a pinch of marjoram in butter, deglaze with soup and simmer for about 6 minutes. Stir in the crème fraîche and simmer for about 1 minute. Set the sauce aside.
Pat the fish fillets dry and remove any bones with tweezers. Cut the fillets into 4 equal pieces, cut across the skin a few times, not too deep, season with salt, pepper and lemon juice. Heat the oil, place the fish fillets skin side down and fry on both sides (1-2 minutes in total, depending on the thickness). At the same time, bring the sauce to the boil, puree with a hand blender and season with salt, pepper and lemon juice. Take the fish fillets out of the pan, let them drain briefly on kitchen paper and serve with the sauce.