Cut, wash and chop the celery leaves and set aside. Clean, wash and cut the celery stalks. Wash the tomatoes too, remove the stalks and cut into quarters.
Puree the celery, tomatoes, chopped onion and peeled garlic cloves in a blender. Mix the puree with the vegetable stock, oregano, paprika paste and the oil, season with salt and sugar. Cover the soup and chill for a few hours.