Seven people connected to the attack on the satirical magazine Charlie Hebdo, have been detained for questioning, as police hunt for two more men.
The arrests were made in the town of Charleville-Mezieres and the cities Reims and Paris.
The two main suspects are still on the run and have been named as brothers, Said and Cherif Kouachi.
The youngest of the suspects, 18-year-old Hamyd Mourad surrendered to French police.
Last night armed police raided an apartment to the east of Paris.
The attack happened at the French satirical newspaper Charlie Hebdo. The magazine has previously depicted a caricature of the Islamic prophet Muhammad.
12 people were killed in the attack. Prosecutor Francois Molins, confirmed eight journalists, two police officers, a maintenance worker and a visitor were killed, and 11 people were wounded, four of them seriously.
A vigil of solidarity was held last night in Trafalgar Square in response to the shootings.
Hundreds of people gathered to pay respect to those killed.
Many held signs which read in French, "I am Charlie" defending the right to freedom of speech.
The Home Secretary, Theresa May will chair an emergency COBRA meeting today in response to the shootings.
Meanwhile, David Cameron has offered his support to French officials investigating the attack by offering the service of the British intelligence services.
London Live’s Alison Earle was at the French embassy, with the latest on the story.
Farooq Aftab, a Human Rights Activist, Lawyer, and News Commentator on Islamic issues, joined Wake up London. He said:
“The Muslim community condemns the attack on Charlie Hebdo absolutely. We offer our condolences to the victims and those left bereaved. Islam does not permit any person to take the law into his own hands. We condemn this attack unequivocally.”