Cut the sausages into slices. Peel and finely dice the onion. Clean, wash and chop the peppers.
Heat the oil in a pot. Fry the sausage for 3-4 minutes while turning it. Add onion and paprika, fry for about 2 minutes. Sprinkle with 1 tsp. curry and sauté briefly. Deglaze with strained tomatoes and stir in curry ketchup.
Bring to the boil and simmer for about 5 minutes.
Season soup with salt, pepper and curry. Serve with yoghurt, sprinkle some curry on top.