The activist flew over the Bugey power station at about 7.40 this morning on a paraglider with motorised propeller, and put the smoke canister on the roof of one of the four central reactors in the compound.
He then took off his yellow paraglider inside the station, where he was reportedly met by security guards.
Greenpeace France’s nuclear specialist, Yannick Rousselet, told Le Parisien: “We did this to demonstrate how vulnerable French nuclear stations are to air attacks, which no one has really considered.
“Just a few days before the second round of elections, we want politicians to take into account this vulnerability and realise the enormous risk nuclear power poses in France.”
Sophia Majnoni, Greenpeace nuclear expert, explained to 24 hour news chanel iTélé: “This is a double risk – an aeroplane could crash or there could be a terrorist attack.”
Last December 11 Greenpeace activists managed to penetrate two other nuclear sites in France.
Following the incident, interior minister Claude Guéant announced nuclear station security would be improved.