Four men in their 20's will appear before a judge in France today to face possible charges of providing support to one of the Paris attackers involved in an islamist attack that left 17 people dead across the city earlier this month.

The Prosecutors' office has confirmed the 4 are among 12 people detained in police raids on Friday.

They will face an an anti-terrorist judge who will decide whether to charge them with providing logistical support.

17 people were murdered and French police have warned up to six terror cell members may still be at large.

The man who killed the four shoppers in a hostage stand-off in Paris "undoubtedly" had an accomplice, France's prime minister says.