Soak the beans with water overnight. Dice the bacon, heat the oil in a saucepan and leave the bacon out. Peel the onions, dice finely, add to the bacon and fry briefly. Add the drained beans and sauté.
Stir in the tomato paste, pour in the broth, bring to the boil and cook the beans for approx. 40 minutes. Peel and core the tomatoes, cut into cubes and mix with the stew shortly before the end of the cooking time.
Season well with salt, pepper, cayenne pepper, sugar and savory. Cut the chives into rolls and fold in.