Sighting in Maisons-Alfort, July 5, 2020

At around 8:30 pm, the witness was looking out of the window of their third-floor apartment when they noticed a black line just below the Moon. Thinking it was the shadow of a cloud, they took several photographs. As they kept watching, the object drifted slowly eastward, leaving the bright halo around the Moon. When they later looked at their pictures, they began to doubt their first explanation of a cast shadow. There was only one witness, but the account was complete and fairly precise, and the phenomenon had been photographed several times, so the case was considered highly consistent.

The GEIPAN investigation concluded that the witness had mistaken the shadow of the condensation trail of a flight from Palermo to London for something unusual. The shape of the line and its slow movement strongly suggested an aircraft contrail or its shadow. The position of the celestial bodies in the photographs made it possible to establish when they were taken: in the stated direction and at the angular height of the phenomenon, that flight was present. Lit by the Moon and well above the clouds, the aircraft cast the shadow of its contrail onto them. The case is classified A: a very probable misidentification of the shadow of an aircraft contrail.