In a large bowl, combine the 5 tablespoons of mayonnaise with the diced celery, 1/2 big onion, bacon, 4 cornichons, 3 hardboiled eggs, 1 teaspoon Maggi Seasoning, 1/2 teaspoon paprika, and 1/2 big lemon's juice. Stir everything until it's evenly mixed. If you don't have Maggi, you can use equal parts dark soy sauce and Worcestershire sauce as a substitute.
When the potatoes are ready, drain them thoroughly in a colander. While they're still warm, add them to the bowl with the dressing and toss until every potato piece is coated. Season with kosher salt and long pepper to your liking, then finish with a pinch of paprika. Transfer the salad to the fridge and let it chill for a while, giving all the ingredients time to meld.