Fransk politi arresterte 12 personer mistenkt for terrorforbindelser tirsdag, herav 9 i Marseille/Avignon mistenkt for våpensmugling. Men det er de tre andre, to i Marseille og en i Bordeaux, som gir et innblikk i undergrunnen som kanaliserer mennesker illegalt inn og ut av Europa og forsyner dem med falske ID-papirer.

Three of the arrests Tuesday stemmed from the arrest of a man on Saturday near the central train station in Naples, Italy. The authorities said he was carrying materials for a bomb.

Two men in Marseille and one in Bordeaux were arrested after their telephone numbers were found in the cellphone of the man arrested in Naples, Ryan Hannouni, the authorities said. Mr. Hannouni, 28, is a French citizen of Algerian origin. France has requested his extradition.

The men were said to be involved with a group offering housing and false identity papers, presumably to foreigners seeking to enter France and to French citizens who want to train or fight in Afghanistan.

Agnès Labrégère, a spokeswoman for the Paris prosecutor’s office, which handles terrorism investigations, said Mr. Hannouni was suspected of “participation in criminal networks aimed at supplying jihad in the Pakistani-Afghan zone.”

France Arrests 12 in Antiterrorism Raids