Updated

French President Francois Hollande is vigorously denouncing suggestions by conservative presidential hopeful Francois Fillon that Hollande has a "cabinet noir" to discredit political rivals.

Fillon told France-2 television Thursday night that he wants an investigation into supposed revelations in an upcoming book that Hollande intervenes in legal cases for political reasons.

Fillon's campaign is flailing because of corruption charges.

Hollande, a Socialist, responded in a statement saying he "condemns these false allegations with the greatest firmness." He insisted he had never intervened in any judicial procedure — including the investigation into accusations that Fillon employed family members for parliamentary jobs they never performed. Fillon denies wrongdoing.

For the first time in generations, neither the conservative nor Socialist party is likely to win the presidency, amid voter frustration with the establishment.