France, Oct. 21 -- At least 3,000 shops were damaged or looted nationwide on 17 and 18 October, with losses estimated at several hundred million euros.

With presidential elections just six months away, the question of who was behind the violence - whether it was politically organised, largely opportunistic or linked to immigration - has become central to the debate over public order and the government's authority.

Some 2,500 people have been taken into police custody in connection with last weekend's violence and 1,000 referred to a judge or prosecutor, the Justice Ministry has said.

Courts using special fast-track procedures have convicted 150 people so far.

"If we don't deliver an extremely firm penal response, then residents will t...