Place potatoes in large saucepan. Cover with water. Bring to boil. Boil 10 minutes or until potatoes are fork-tender. Drain well in colander. Let cool.
Mix mayonnaise, sour cream, mustard, celery salt, and pepper in large bowl until well blended. Add potatoes, celery, and onion; toss gently to coat. Gently toss in eggs. Cover.
Refrigerate until ready to serve. Stir and sprinkle with additional paprika before serving.