Bring a large pot of water to a boil over high heat on the stove. Add the potatoes and cook for 15 minutes. Drain.
In a large bowl combine the mayonnaise, sour cream, Dijon, yellow mustard, vinegar, salt, pepper, and celery salt. Mix well.
Gently stir in the onion, celery, and fresh herbs.
When potatoes have cooled mix them into the dressing. Refrigerate for at least 4 hours before serving.