Clean, peel, and chop the onions, garlic, and carrots.

Sauté the chopped onions, garlic, and carrots in butter with chili flakes and paprika in a pot - without browning the vegetables. 

Add the broth, tomato paste, and chopped tomatoes, and let everything simmer until the vegetables are tender.

Blend everything with an immersion blender or in a regular blender. 

Pour everything back into the pot, where the soup is heated up and seasoned with lemon juice, sugar, apple vinegar, and salt and pepper.

Serve the hot soup with a spoonful of crème fraîche in the middle.