The extraordinary 12-day state of emergency, which began Tuesday at midnight, is authorized under a 50-year-old law dating back to France's colonial war in Algeria that allows officials to put troublemakers under house arrest, limit people's movements, confiscate weapons and close public spaces, according to the Associated Press.
The emergency decree also paves the way for curfews, which a few municipalities and regions have imposed.
"I have asked regional prefects to expel foreigners who were convicted -- whether they have proper residency papers or not -- without delay," said Interior Minister Nicolas Sarkozy, who had previously inflamed passions by referring to the rioters as "scum."
The riots began Oct. 27 when two teenagers of Mauritanian and Tunisian descent were accidentally electrocuted while hiding from police in a power substation.
The incident grew into a nationwide insurrection by disillusioned suburban youths who are complaining of discrimination and unemployment. Rioters have burned thousands of cars and buses, killed one elderly man and injured more than 100 police and fire personnel.
The violence has been showing signs of slowing. From late Tuesday through early Wednesday, youths torched 617 vehicles, down from 1,173 a night earlier, national police spokesman Patrick Hamon said, the AP reported.
Incidents were reported in 116 towns, down from 226. In all, police have arrested 1,830 people.
"The arrests are bearing fruit," Interior Ministry spokesman Franck Louvrier said, according to the AP. "It's clear there has been a significant drop, but we must persevere."