French policemen guard the entrance of the anti-corruption office of the French police (Oclciff) on July 1, 2014 in Nanterre, near Paris. Nicolas Sarkozy was on Tuesday detained for questioning at the Oclciff in Nanterre, in a widening corruption probe, a judicial source told, in an unprecedented move against a former French president. Sarkozy had turned himself in for questioning a day after investigators detained his lawyer Thierry Herzog and two magistrates. The investigators are seeking to establish if the former president, with the help of Herzog, attempted to pervert the course of justice. AFP PHOTO / DOMINIQUE FAGET