French billionaire politician Olivier Dassault has been killed in a helicopter crash, French President Emmanuel Macron has confirmed.

The 69-year-old MP was reportedly in a private helicopter flying over Normandy, where he had a holiday home.

The Bureau of Investigation and Analysis for Civil Aviation Safety said in a tweet that the aircraft, an Aerospatiale AS350 Squirrel, had crashed “on takeoff”. It had been leaving a private property, investigators said.

Mr Dassault was the eldest son of billionaire industrialist Serge Dassault, whose group builds the Rafale war planes and owns Le Figaro newspaper.

It’s believed Olivier Dassault had been at his holiday home near Touques in northern France. Photo: Getty

“Olivier Dassault loved France. Captain of industry, lawmaker, local elected official, reserve commander in the air force,” Mr Macron said on Twitter on Monday (Australian time).

“During his life, he never ceased to serve our country, to value its assets. His sudden death is a great loss. Thoughts on his family and loved ones.”

Olivier Dassault aimait la France. Capitaine d’industrie, député, élu local, commandant de réserve dans l’armée de l’air : sa vie durant, il ne cessa de servir notre pays, d’en valoriser les atouts. Son décès brutal est une grande perte. Pensées à sa famille et à ses proches.

— Emmanuel Macron (@EmmanuelMacron) March 7, 2021

A lawmaker for the conservative Les Republicains party since 2002, Mr Dassault was considered the 361st richest man in the world alongside his two brothers and sister.

He had stepped down from his role on the board of his family’s company due to his political role to avoid any conflict of interest.

Olivier, seen as the favourite of founder Marcel, was once considered favoured to succeed Serge at the head of the family holding, but that role went to former Dassault Aviation CEO Charles Edelstenne.

-with AAP