I just found it to JT FR2, it is less than 1 year that it exists.
Mission (after the wikipedia):
The national energy mediator is responsible for participating in informing consumers about their rights and recommending solutions to disputes arising from the execution of supply contracts, which have been the subject of a prior written complaint, between private consumers or "small professionals" and electricity and natural gas suppliers.
The official site: http://www.energie-mediateur.fr/ (apparently in the process of being "changed")