Retail royalty, the Mulliez family has been involved in the industry since the 19th century, when patriarch Louis Mulliez-Lestienne founded clothing chain Phildar in the northern French city of Roubaix. Inspired by America's self-service stores, his grandson Gérard Mulliez (pictured) set up supermarket chain Auchan in 1961 and hasn't looked back.
The firm, which is still family-owned, now boasts more than 4,000 locations worldwide, and the Mulliez family is worth $38.4 billion (£31.9bn), according to Bloomberg.
Meanwhile, Gérard's cousin Michel Leclercq and his family have a fortune of $3.1 billion (£2.6bn) from his sporting store Decathlon.