The group announced that it staged the break-ins in advance of the upcoming French presidential elections in an effort to encourage the two remaining candidates, incumbent Nicolas Sarkozy and the Socialist Party's Francois Hollande, to reverse their positions on nuclear energy.
Though one of the protesters was found hiding in a bush outside the area with the nuclear power reactors, one activists using a paraglider was able to drop a smoke bomb on the roof of a reactor building. This is the second such instance in the past six months, but officials were quick to reassure that the activists posed no realistic threat to the power plants.
"At no time was the security and safety of the installations called into question," said a spokeswoman from Électricité de France SA, which owns the plants, according to the Journal.
The International Energy Agency reports that in 2009 nuclear power accounted for more than three-quarters of France's electricity production, one of the highest proportions in the world.