The kite-shaped pink jewel is believed to have been passed down from France's Queen Marie Antoinette to her daughter.

For Novak Djokovic, this is a relatively easy call. He thinks the French Open is making a mistake by eschewing the electronic line-calling used at most big tennis tournaments.

Currently, it has four locations across Paris in Pigalle, Marais, Petites-Ecuries and Oberkampf, but as of next month it’s ...