Peel and finely chop the garlic. Wash marjoram, shake dry, put 4 stems aside for garnishing, pluck remaining leaves from the stems.
Heat the oil in a pot. Sauté the garlic in it. Add lentils, marjoram and tomato paste and sauté briefly. Pour on 1 l water, bring to the boil and stir in broth. Add savory. Covered lentils and simmer for about 15 minutes.
Clean and wash the celery and cut it into fine slices. Wash and halve the cherry tomatoes. Add both to the lentils about 5 minutes before the end of the cooking time.
Season lentil soup with salt, pepper and sugar. Mix horseradish and crème fraîche. Arrange soup in bowls. Garnish with remaining marjoram and add the horseradish cream.