During the 2005 riots, Sarkozy, who was then interior minister, described the young immigrant rioters as "scum" and promised a harsh crackdown. His admirers praise him as a tough proponent of law-and-order while foes see him as a dangerous authoritarian figure who panders to anti-immigrant sentiments.
Now, Sarkozy is the son of a Hungarian immigrant(and has a Jewish grandfather). What that means in concrete terms is it will be hard to call this guy a "Nazi" in politically correct France—even if he actually started mass deportations to solve France's immigration issues. Right now, the market at Intrade.com gives Sarkozy about a 72% chance of victory in the run off election.
I suspect that the immigration issue will continue to become even important in France. This was the last election in which Le Pen will likely be running. Immigration was alway the signal major issue for Le Pen. However, Le Pen managed to acquire a rather unsavory reputation with much of the electorate—which meant that when he did manage to get into the run-off election he did barely any better than when he was in the multi-candidate election.
Sarkozy's candidacy is arguably an attempt by the French mainstream to grab some of Le Pen's support—and that will even a bigger factor the next French presidential election.
The question now becomes what range of policies immigration restriction in France is likely to be bundled with. We haven't yet seen the French counterpart of Pim Fortuyn—but I suspect France may soon be ready for something similar.