In a large pot, place the potatoes in cold water and bring to a boil. Cook until potatoes are fork tender, approximately 15 minutes. Remove potatoes from pot and place on a serving dish. Add butter randomly on top of potatoes and sprinkle with fleur de sel.
Preheat the grill.
Place sardines and ham on grill. The sardines will only take a few minutes to cook, approximately 3 minutes on each side. Once the ham is done remove from grill.
Divide potatoes, sardines, and ham on each plate. Sprinkle with a little fleur de sel and serve.