Yes, the lex solis applies in France as well as the lex sanguinis, so whether one is born in France or born of French parents, one is a French citizen.
Citizenship can be removed, however, and lex solis citizenship of illegals is more tenuous than it would be for a clear native-born French.
There is tremendous discretionary power in French government, and appeals are taken to a separate judicial system from the regular civil courts.
Did you see this?
http://www.lemonde.fr/web/article/0,1-0@2-706693,36-708056@51-704172,0.html
Le détail des mesures
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My translation of the important parts:
Every unemployed person under the age of 25 will be ordered to report to an unemployment office for 3 months of "vocational assessment". At the end of three months, they will either be contracted to take a government job, given further training or assigned to something ominously labeled "formation".
Twenty thousand or more new government jobs will be created.
Some of the new jobs ("adult-relay") will be neighborhood snitches who will root out the under-25 hippies who are freeloading and not reporting for "formation".
5000 of the the new government jobs will be High School aides. (Brilliant. They're letting the free-loaders into the high schools to spread the culture of free-loading.)
Some students will be allowed to start vocational training at 14-years instead of 16-years-old.
Ten boarding schools will be opened for the intelligent from poor neighborhoods. This will isolate these students from the bad influences of their cultures. (Taking the brightest and the best off to boarding schools for French assimilation).