Wash the potatoes well and boil in salted water for about 20 minutes. Boil eggs hard for 10 minutes. Stir sour cream and mayonnaise in a bowl until smooth. Wash the herbs, dab dry (put some aside for garnishing) and chop finely.
Peel and finely chop the onion. Stir both into the sauce. Season to taste with salt and pepper. Drain the potatoes, rinse with cold water and peel the skin. Peel and halve the eggs. Arrange potatoes, egg halves and green sauce.
Garnish with herbs and sprinkle with coarse pepper to taste.