Peel and finely chop the onions and ginger. Peel the sweet potatoes and carrots and cut into cubes.
Heat the oil in a saucepan and sauté the onions and ginger. Add sweet potatoes and carrots and sauté briefly. Pour in the broth, season with paprika, salt and pepper and simmer for about 20 minutes.
Mix the soup with the hand blender until smooth, stir in the crème fraîche and season to taste.