Make a dressing from oil, vinegar, mustard, salt, pepper and sugar. Put the onions, meat sausage and peppers in a bowl. Pour the dressing over it and mix all the ingredients well. Cover the salad and let it steep in the refrigerator for a few hours.
Mix again shortly before serving, decorate with parsley and eggs. Fresh baguettes and a cold beer go well with this. The salad is also good on buffets.