Boil small potatoes in their skins. Potatoes should not be larger than a quail egg. Cut into halves.
Blanch the string beans in boiling water for 5 minutes, drain the water and immediately place the beans in cold (or better, ice) water so that they retain their color. Drain the water and dry the beans on a napkin.
Small tomatoes cut into 4 parts. Combine the vegetables in a bowl, add salt, shake the bowl.
For the dressing, mix the fresh cream, chopped parsley, grain mustard and olive oil.
Put the vegetables in a salad bowl and put the dressing on top. This salad is not made to mix when serving. Everyone mixes it in their portion salad bowl.