Sighting in Épinay-sur-Seine, May 4, 2015

At around 4 a.m., just after waking up, the witness noticed a triangular shape crossing the sky, outlined by lights at its corners. It passed at a right angle in front of their terrace, at the height of a low-flying aircraft. The witness also heard a noise like that of an airplane flying low. No other witness came forward.

The phenomenon had many characteristics of an aircraft: steady white-yellow lights, flashing red and white lights, and a matching apparent size and sound. Because the witness could make out neither a fuselage nor wings, they perceived a triangular shape, which struck them as strange. GEIPAN explains that observers often interpret a group of light points as an object bounded by those points. This shape or contour illusion also occurs with aircraft whose wings are hard to see. The witness may have missed the wings because they were seen edge-on, or more probably because the aircraft was very dark, as large military transport planes are.

The axis of one of the Le Bourget runways passes over Épinay-sur-Seine, 7.5 km away. The Météociel record shows a south-westerly wind at Roissy, so aircraft were taking off toward the west, in the direction of Épinay. GEIPAN classed the case as B, a probable aircraft. The case was handled too late to check with air traffic control whether a flight had actually taken place at that time.