French industrialist Serge Dassault, the billionaire manufacturer of fighter jets, was in custody Wednesday for alleged vote buying, a judicial source said.
The move comes a week after Dassault's parliamentary immunity was lifted. The senator is suspected of buying votes in Corbeil-Essonnes, east of Paris, where he was formerly mayor.
He has been accused of running the suburb like a mafia don.
The 88-year-old is being grilled in the western Paris suburb of Nanterre, the source said.
Dassault is ranked by Forbes magazine as France's fourth-richest man and the 69th-richest in the world with an estimated fortune of 13 billion euros ($18 billion).
The judges suspect Dassault of operating an extensive system of vote buying which influenced the outcome of three mayoral elections in Corbeil in 2008, 2009 and 2010, which were won either by Dassault or by his successor and close associate Jean-Pierre Bechter.
The result of the 2008 vote, won by Dassault, was invalidated by the Council of State after the body which oversees public administration discovered a series of payments which could have influenced the outcome of the election.
[Image via Agence France-Presse]