Wash the potatoes thoroughly and boil them in boiling water for about 15 minutes until soft. Peel the shrimps, except for the tail fin, and remove the intestines. Wash shrimps and pat dry. Heat 1 tablespoon of oil in a frying pan. Fry the prawns for 3-4 minutes over a high heat, turning them over, season with salt and pepper.
Wash the salad and herbs and drain well. Dab the herbs dry and chop them coarsely. Drain potatoes, rinse briefly in cold water, peel and cut into thick slices. Leave to cool down a little. Mix vinegar and mustard, season with salt, pepper and sugar. Fold in 4 tablespoons of olive oil, season to taste
Mix prawns, herbs, potatoes and salad. Distribute on small bowls and serve or keep covered and cool until serving