Soak the beans overnight in plenty of cold water. Drain the beans, measure 1 litre of soaking water. Bring the beans to the boil and cook for approx. 1 hour at medium heat. Peel and finely dice onions and garlic. Wash the chilli pepper, halve lengthwise, remove seeds and dice finely.
Clean and wash the bell peppers and cut them into small strips. Heat oil in a pot. Sauté onions, garlic and chilli pepper in it. Add tomato paste and paprika powder. Deglaze with 1/4 litre water. Add the beans with the cooking water. Bring everything to the boil. Season with salt and pepper. Add paprika, bay leaf and thyme and cook for another 15 minutes.
Add the beans with the cooking water. Bring everything to the boil. Season with salt and pepper. Add paprika, bay leaf and thyme and cook for another 15 minutes. Slice the sausages and add them to the beans 5 minutes before the end of the cooking time. Season soup with salt, pepper and ketchup