Minors have special rights!
Guide for minors in France
France has the obligation to protect minors in difficulty, what means offering good living conditions, education, opportunities to learn a job. It is possible for minors who choose to stay in France to leave in a camp or in a family, to go to school or to learn a job, under the responsibility of the Childhood Social Help. Some solutions exist for them to stay in France after 18, but it depends on their situation. It is sometimes difficult to proof you are under 18, even if you have identity papers.
Your rights and how to proceed if you are a foreign minor: