Electricité de France (EDF) has been convicted in a French court of spying on Greenpeace as it campaigned against the UK government’s plans to work with the energy company to expand its nuclear operations.

EDF was fined €1.5m and ordered to pay Greenpeace €500,000 in damages for non-material loss after hiring a hacker and a private investigator to spy on Greenpeace France’s operations. Two EDF nuclear safety staff and two staff from Kargus Consulting, which was hired to undertake the undercover investigation of Greenpeace, were convicted during the trial which wrapped up on 10 November.

The trial concluded that Kargus Consulting had hacked the computer of Greenpeace France’s director at the time, Yannick Jadot (pictured), who left the organisation in September 2008 to further his environmental aims through politics. The court found EDF and Kargus guilty of "complicity and concealment of fraudulent computer intrusion" to the detriment of Jadot.

EDF hired Kargus Consulting to monitor Greenpeace in 2006, after the charity challenged plans by the UK government to work with EDF on increasing nuclear energy output, which Greenpeace claims is “inherently dangerous”. The head of the consulting company, Thierry Lorho was sentenced to three years in prison with a two-year suspended sentence, while a Kargus computer specialist, Alain Quiros, was sentenced to two years in prison with an 18-month suspended sentence. Both were fined €4,000.

Pascal Durieux, head of nuclear safety at EDF in 2006 was sentenced to three years in prison, with two years suspended, and received a €10,000 fine. His deputy, Pierre-Paul Francois was sentenced to three years in prison with 30 months suspended.

Adélaide Colin, Greenpeace France communications director, said: "The fine against EDF, and the damages awarded to Greenpeace send a strong signal to the nuclear industry that no one is above the law."

EDF France refused to comment on the trial results.