Wash the potatoes and cook for about 20 minutes. Clean, wash and halve the beans. Cook in boiling salted water for about 15 minutes. Drain the beans. Drain potatoes, quench, peel and let them cool down.
Wash the tomatoes and cut them into slices. Peel and halve onions and cut them into fine slices. Clean, wash and cut the romaine lettuce into strips. For the marinade, beat lemon juice, vinegar and olive oil.
Season with salt, pepper and sugar. Pluck basil leaves and stir into the marinade. Cut potatoes into slices and sprinkle with the marinade. Fold in other prepared ingredients. Wash the fillet, dab dry and cut into 12 medallions.
Wrap 1 slice of bacon around each one and put 3 pieces on each skewer. Heat the oil in a pan. Brown the skewers on each side. Season with salt and pepper and fry for about 6 minutes.
Season salad again and arrange with the skewers. Serve garnished with lemon and basil.