Wash the potatoes and cook in boiling water for about 20 minutes. Then rinse with cold water, peel and leave to rest for a while. In the meantime, wash the chicken fillets and pat them dry.
Fry in 1 tablespoon of hot oil all around for about 12 minutes. Clean the chanterelles and fry for 2-3 minutes. Season everything with salt and pepper. Peel onions and cut them into thin rings. Clean, wash and slice the tomatoes.
Wash the chives and cut into small rolls. Cut the potatoes into slices. Mix with tomatoes and chanterelles. Heat vinegar. Add onion rings, take aside. Stir in remaining oil, mustard and chives.
Season with salt, pepper and sugar. Mix with the prepared salad ingredients, let it stand for a while. Cut the chicken fillets open, arrange on the salad and serve. Serve garnished with chives.