"At present, nine people are detained," Cazeneuve said at a press conference.
On Wednesday, three men attacked the office of the magazine in central Paris, killing 12 people and injuring a further 11. Earlier, it was reported that seven individuals, possibly linked to the attack, had been arrested, with a nationwide manhunt underway for two more gunmen.
The third suspect has surrendered himself to the police, saying he did not take part in the attack and had an alibi.
The Charlie Hebdo magazine has received threats from radical Islamists in the past over the publication of caricatures of the Prophet Muhammad. Prior to Wednesday's attack, the magazine posted a cartoon on Twitter depicting the leader of the Islamic State militant group, Abu Bakr Baghdadi.
