Sarkozy will replace 74-year-old President Jacques Chirac.
The French election probably reflects the deep uneasiness of a nation caught resting while the world around is changing.
French air investigators are examining one of the black boxes of the doomed Germanwings plane to find out why the aircraft crashed into a mountain in the French Alps, killing the 150 people on board.
Across the world rallies were held to draw attention to climate change ahead of a United Nations summit in New York.
Volkswagen is under huge pressure to act, with its shares down more than a third in value since the crisis broke, and the bad news still coming.