Preheat the broiler.
In a medium-size mixing bowl, combine the tuna, tarragon, basil, parsley, olives, shallots and capers. Squeeze the lemon over the bowl, being careful not to get any of the seeds in. Drizzle in the EVOO and season with salt and freshly ground black pepper. Mix thoroughly to combine. Reserve in the fridge until ready to serve.
Preheat a large skillet over medium heat. While the skillet is heating, brush the baguettes with the melted butter. Toast in the skillet until golden brown. Fill the baguettes with the tuna salad. Top with gruyere cheese and pop under the broiler until the cheese is melted and bubbly. Serve with carrot and celery sticks, and healthy potato chips alongside.