North Africans constitute 10% of the French population; Muslims constitute 10%; Naturally, these two figures predominantly overlap.
http://en.wikipedia.org/wiki/France#Demography
On voting: Did you know that in American elections prior to 9/11, Muslims (other than Black Muslims) voted 60% Republican?
Muslims in France vote as a bloc, and Sarkozy is not their chosen leader. In 2000, Muslims were around 10% of the population in France. But native French average 1 baby per woman, while Muslims in France average 2.6 babies per woman. That means that already 25% of first-graders in France are Muslim, and by 2035, 60% of first-graders will be Muslim.
The Roma are a small minority. Many young adults leave the Roma community, looking for honest work. But in this economic environment, not so much.