The accident happened in the afternoon shortly after take-off from the Versoud airfield near Grenoble in southeast France, for what should have been a half-hour flight.
Eye-witnesses to the crash tipped off the emergency services, who found the bodies of four adults and a child inside the plane's burnt-out wreckage.
Around 60 firefighters were deployed to the site to put out the fire.
Grenoble prosecutors have ordered an investigation into what happened, said regional officials.