1. Cut 1/3 of the smaller side of the egg and then trim a slice off the larger side (bottom) to allow egg to stand up. Carefully remove yolks and set whites aside.
2. In a small bowl, mash yolks with a fork. Add the crème fresh, sugar, vinegar, mustard and salt; mix well. Spoon or pipe into egg whites. Refrigerate until serving.
3. Before serving, top each egg with a small spoonful of black caviar.
4. Garnish with sprig of chives.