Sighting in Le Plessis-Trévise, June 20, 2017

In the late morning, the witness was at a friend's home when the sound of a helicopter caught their attention. They stepped out onto the balcony and searched the sky for the aircraft. Instead, in broad daylight and under a clear sky, they saw luminous points whose number grew from 1 to 3, then to 6. The points moved about with rapid changes of direction and then vanished all at once. Later the same day, the witness again saw similar movements, this time of a single luminous point. The next day, back at their friend's home at around 12:10 pm, they saw a luminous point again in the same area, under a cloudier sky, but did not watch it for long. Only one account was collected.

The investigation looked at several explanations. Flying lanterns were ruled out because the sighting took place in the middle of the day. Balloons, possibly connected with the Fête de la Musique, fitted poorly with the weak wind and the varied trajectories. Circling birds were the most consistent explanation: light-coloured wings, lit indirectly by atmospheric scattering while the sun was very high, and seen from far away, could appear on their own as luminous points, especially during soaring flight.

The strangeness of the case was rated low and its consistency medium: a single witness, no photograph, some doubt about the actual date (the witness mentioned clouds that were absent or scarce that day), and few reports despite a heavily urbanised area. GEIPAN classified the case as B: probable misidentification of sunlight reflecting off flying birds.