The seven, connected to the two main suspects, were detained in the towns of Reims and Charleville-Mezieres, as well as in the Paris area, police said.
Photos were released of two brothers suspected of involvement in the attack.
France is mourning the 12 people killed when Charlie Hebdo was targeted by gunmen shouting Islamist slogans.
Reports are coming in from Paris of a shooting at a metro station in the south of Paris. At least one police officer is reported to have been injured. It is not known whether the incident is linked to the attack on Charlie Hebdo.
President Francois Hollande is conducting an emergency cabinet meeting in Paris.
A minute’s silence will be observed at midday across the country and the bells of Notre Dame in the capital will toll.
Arrest warrants were issued for Cherif Kouachi, 32, and his brother Said Kouachi, 34, said to be “armed and dangerous”. A third suspect, Hamyd Mourad, a brother-in-law of Kouachi brothers, has surrendered.
Cherif Kouachi was sentenced in 2008 to three years in prison for belonging to a Paris-based group sending jihadist fighters to Iraq.
A third suspect, 18-year-old Hamyd Mourad handed himself in to police in Charleville-Mezieres. He reportedly surrendered after hearing his name on the news.
3CIrye0Lz10Image source: Wikimedia Commons President-elect Donald Trump celebrated his election victory at the Ultimate Fighting…
Millions of voters across the US chose to return Donald Trump to the White House…
Donald Trump declares victory in the US election as he addresses jubilant supporters in Florida.…
Stocks around the world are rising as Donald Trump appears to be on the cusp…
Donald Trump has won Pennsylvania, North Carolina and Georgia and taken a lead over Kamala…
Quincy Jones, the celebrated musician and producer who worked with Michael Jackson, Frank Sinatra, Ray…