This morning on our way back from Paris at around 2.45am, having just left the A6, we arrived in Mennecy by rue du Paris where the Garage SVO is situated; just before the RER D level crossing and Gare du Mennecy. We had seen blue lights everywhere from a distance, but on arriving where the traffic lights and garage are we saw Gendarmes and Pompiers everywhere. Looking to the right (see Google Streetview above), the parking area was crammed with cars one of which was well alight. We were waved through the lights and the level crossing and by the time we climbed Avenue Darblay another fire engine was on its way with lights flashing to join the other one at the scene.
I can only hope that they managed to put the fire out quickly, as I would hate to think what would have happened if the fire had spread to the other cars. The parking area was certainly well packed with cars.