A Greenpeace activist on a motorised paraglider dropped a smoke bomb onto the roof of a French nuclear reactor near Lyon today to stimulate a political debate on nuclear power.
The German national then crash-landed in the interior of the Bugey nuclear power plant enclosure, where he was arrested.
A second activist was arrested outside the site suspected of having guided the pilot.
Plant owner EDF has defended the site's security measures, saying in a statement they "were strengthened in late 2011 to allow detection and immediate apprehension of the perpetrator."
Greenpeace nuclear spokesman Yannick Rousselet said that the spectacle demonstrated the vulnerability of nuclear facilities.
"There is no such thing as safe nuclear," Mr Rousselet declared.
"We're four days away from a presidential election and neither President Nicolas Sarkozy nor Francois Hollande is taking the issue seriously.
"Seventy-five per cent of French electrical consumption is nuclear and this needs to drop. We hope this will be a talking point in tonight's TV presidential debate."
Greenpeace activist Sophia Majnoni added: "While Germany took into account the possibility of an aircraft crash in its safety testing, France still refuses to analyse this risk for our plants.
"Post-September 11, this risk must be seriously studied."
French Interior Minister Claude Gueant vowed to bolster the "passive protection" of nuclear plants after 11 Greenpleace activists evaded security at nuclear plants at Nogent-sur-Seine and Cruas on December 5.