By Inti Landauro 

PARIS-- Isabelle Kocher, Engie's deputy chief executive, will take the top job at the company, formerly known as GDF Suez, in May. She will replace the longtime CEO Gérard Mestrallet who is due to retire.

"Isabelle will become the boss of this group in May," Mr. Mestrallet said Thursday during a meeting with reporters to discuss the company's plans this year. She will become the first woman to lead a company in the Paris CAC-40 benchmark stock index, he added.

Ms. Kocher was appointed deputy CEO late 2014 as part of a succession plan for Mr. Mestrallet, who has led the company for two decades. She had been Engie's chief financial officer for three years before becoming deputy CEO.

The changing of the guard comes at a difficult time for the company, which faces plummeting energy prices and weak demand for energy in the European Union.

During the same news conference, Ms. Kocher said the company plans to speed up asset sales to adapt the company to new market conditions. She said the company wants to boost its exposure to renewable energy sources and depend less on thermal energy and mature markets in Europe.

Mr. Mestrallet has led GDF Suez since the 2008 merger between the state-owned utility and Suez, which he had led since 1995. He said the company's board will evaluate whether to give him another role in the company after May.

Write to Inti Landauro at inti.landauro@wsj.com

(END) Dow Jones Newswires

January 14, 2016 04:47 ET (09:47 GMT)