Several executives would be suspended, the investigators said of the accident which also killed three crew members. They added that the driver of the snow-clearing machine was drunk on the job -- a claim disputed by his lawyer.
At Total, one of the world's biggest oil companies, staff at its Paris headquarters observed a minute's silence for their charismatic 63-year-old boss, who had been known by the affectionate nickname "Big Moustache".
One of France's best-known business leaders, De Margerie was an outspoken critic of Western sanctions against Russia over the Ukraine crisis, and just hours before his death had met Russian Prime Minister Dmitry Medvedev at his country residence outside Moscow to discuss investment, local media reported.
Even as relations between the West and Russia deteriorated to the worst since the Cold War, the French oil boss had criticised the sanctions, calling them "a dead-end" and urging "constructive dialogue" instead.
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In France, President Francois Hollande said he learnt of De Margerie's death with "shock and sadness", while Prime Minister Manuel Valls said France had lost "a great captain of industry and a patriot".
Vnukovo airport said the Falcon Dassault business aviation jet crashed as it prepared to take off for Paris. Visibility was 350 metres (yards) at the time, it said, as Moscow saw its first snowfall of the winter yesterday.
Images on Russian television showed the remains of the Falcon-50's charred cabin on the grass near the runway, its tail and one of the engines close by.
Poor weather, an error by air traffic controllers and the alleged drunk snowplough driver will also be investigated as possible causes of the crash, it said. France meanwhile has dispatched three experts to join in the probe.