The private beaches of Menton are along the Bay of Garavan.
This one is called La Pergola (there's a restaurant here too) and this man is sifting pebbles by throwing spadefuls of them at this contraption. Small pebbles are retained - the bigger ones chucked out further down the beach. I presume the uniformity is so that the beach chairs and tables, which will soon be in position for the season, will be on a reasonably even surface.
I had lunch here the other day and this was the entertainment.