Simmer eggs in gently boiling water for 10–12 minutes. Drain and cool in ice water.
Peel cooled eggs. Pat dry, then chop into bite-size pieces.
Stir mayonnaise, Dijon, and lemon juice in a medium bowl until smooth.
Fold in chopped eggs, celery, red onion, and dill. Mix gently to coat.
Add relish if using. Season with salt and pepper to taste.
Dust with paprika. Serve right away or chill 10 minutes for best flavor.