Gérard Mestrallet, who for 15 years has run Engie (a giant energy utility formerly known as GDF Suez) will be replaced as CEO in May by his deputy, Isabelle Kocher, letting Engie celebrate something extremely rare, a female leader of a company in the CAC 40 index. This has only happened once before. (Continental Europe lags on corporate gender equality: none of Germany’s DAX 30 firms has a female CEO or chairman). However it seems that Ms Kocher will not have the run of the place. Her predecessor may hang on for two more years as chairman. Engie’s board meets this month and may confirm the news then. Assuming she remains just CEO, and does not in time become chairman too, Engie is joining a growing club of French firms that split their main leadership roles.That is something shareholders increasingly demand, arguing that having two leaders reduces risks in times of crisis, complexity and increasing regulation.