Authorization to leave the country
As of 15 January 2017, a minor child who lives in France and travels abroad alone or without his / her parents must be issued with an exit permit. It is a form established and signed by a parent (or legal guardian). The form must be accompanied by a photocopy of an identity document from the signing parent.
Find all the information on the website of the French Administration
Download the document cerfa Authorization to leave the territory (PDF)