Boil the potatoes in salted water with caraway seeds as jacket potatoes, drain and allow to cool. Peel the cold jacket potatoes and cut into cubes. Also cut the beetroot into cubes and add to the potato cubes with the capers.
Mix the sour cream, crème fraiche, mustard, salt, pepper and sugar into a salad sauce, season well and pour over the salad. Mix carefully, refrigerate for a few hours and let it steep.
Stir again before serving, seasoning if necessary. Cut the rinsed chives into rolls and sprinkle over the salad.