Sarkozy, who was charged two weeks ago with corruption and influence peddling in a case related to his campaign to win the presidency in 2007, claims he is the victim of a "grotesque" set-up. He accuses his enemies of using the justice system to undermine a possible political comeback.
But according to extracts from tapped calls published by the French daily Le Monde today, the ex-president appears to lobby for a job for the judge in Monaco in return for his help on one of six bribery and funding scandals in which Sarkozy is embroiled.
In intercepted mobile phone calls with his longtime lawyer - who also faces charges - Sarkozy is alleged to have said, "I will help him (the judge)... I will get him set up," adding, "Call him today and tell him I will sort it out. I am going to Monaco and I will see the prince (Albert)."
The conversations are alleged to have taken place in February this year on a mobile phone the 59-year-old politician bought using a false name.
The senior magistrate at the centre of the case, Gilbert Azibert, has been charged with illegally passing on information about the a long-running political funding scandal involving the billionaire L'Oreal heiress, Liliane Bettencourt.
He did not get the position in Monaco, a principality on the Riviera which is largely dependent on France.
In another alleged extract, Sarkozy told his lawyer to tell the judge that he was meeting that day with Monaco's Minister of State (prime minister) Michel Roger and would keep him informed of how it went.
But according to the newspaper, the authorities believe Sarkozy discovered that his "secret" telephone was being tapped and may not have asked for the job for the judge.
Under French law it a crime to promise a public position as a favour, whether or not the position is given to the person.