Patrick Buisson, once chosen to be among Sarkozy's closest aides, was quickly labeled a traitor by members of Sarkozy's party, the UMP.
Henri Guaino, one of Sarkozy's closest allies, said the former president "thought that their relationship was based on, if not friendship, at least trust."
French media revealed Buisson had recorded hundreds of hours of private meetings and conversations with Sarkozy when he was president.
Sarkozy himself is shown to have been dissmissive, even mocking, of the capacities of some of his ministers, in particular as he and his advisors discuss replacing Interior Minister Brice Hortefeux.
Illicit recordings published by satirical weekly Le Canard Enchaîné also contain excerpts in which top official express scorn over the presence of Sarkozy's wife, the ex-supermodel Carla Bruni, at meetings at the Elysée.
Buisson claimed through his lawyer to have made the tapes in the interest of accuracy but there was little leeway from Guaino.
"It is really a betrayal," said Guaino, "for us the experience is akin to a type of rape."
Others were more dismissive, including Sarkozy-era agriculture minister Bruno Le Maire who said "Is it at the heart of the concerns of France, where 9,000 people lost their jobs last month? No. Political leaders have to focus on the concerns of the people, because God knows they are many."
Dismissive and degrading comments about former ministers are about as bad as it gets in terms of the tapes' content.
But more recordings may exist and they could affect the former president, who is thought to be planning a comeback for the next election in 2017.