UPDATE:
According on live french news channel France24, a DGAC spokesm said there was NO emergency call from the cockpit, they speak about a DETRESFA which means aircraft dissapeared suddenly from radar and lost comunication. The ATC launched the DETRESFA for finding the plane. The place seems difficult accesible only via helicopters. It's also reported that the black boxes are retrieved. The DGAC and France24 talks about a possible lost of control of aircraft.
Waiting for more news...