Heat grill to a low heat level. In a large bowl, combine 1/3 cup oil with 1/2 tsp. salt and pepper. Add potatoes, peppers and onion. Toss to coat and spread out on a jellyroll pan.
In the same bowl, combine garlic, 2/3 cup oil, mustard and remaining 1/4 tsp. salt and pepper. Whisk in vinegar until combined.
Place all vegetables on the grill and cook for 6 - 20 minutes or until tender and slightly browned, turning halfway through cooking time. (Grill peppers 6-8 minutes; onions 8-10; potatoes 15 - 20.) Remove from the grill and coarsely chop peppers and onions.
While vegetables are still warm, toss them together in a large clean bowl with the chopped eggs and Ile de France Camembert until the cheese melts slightly. Drizzle with dressing, sprinkle with chives, garnish with cornichons and serve warm.