They are being questioned about "possible logistical support", such as guns or weapons, that they could have given the gunmen, a judicial source told AFP.
Police conducted raids in five towns in the Paris region, iTele reported.
Last week`s violence began with an attack on the Charlie Hebdo magazine.
A kosher supermarket and police were also attacked.
Police carried out raids in the towns of Montrouge, Grigny, Chatenay-Malabry, Epinay-sur-Seine and Fleury-Merogis overnight, iTele reported.
Meanwhile, German police say they have arrested two suspects following raids on suspected Islamist sites early on Friday.
Neighbouring Spain has also launched an inquiry after it was revealed that one of the Paris gunmen, Amedy Coulibaly, had visited Madrid days before the attacks.
Paris attacks: `Twelve arrested overnight`
16 January 2015
Read: 911
Twelve suspects have been arrested in the Paris region over last week`s attacks in the French capital that killed 17, reports say.
