Sighting in Paris, September 26, 2024

A witness went down into the courtyard of their residence and noticed a blue halo in the sky at 9:16 p.m. It looked stationary and lay toward the north-east of the capital. The sighting lasted a few seconds, under a minute in total. The halo was visible at height, but its shape and size could not be made out precisely. The glow was slightly unstable, vibrating while staying in place. It then shifted very quickly to the right and vanished almost instantly toward the east. The witness took two identical photos with their smartphone, one of which carries a timestamp, and then a last one just before the disappearance.

The investigation rests on this single account. Its consistency was rated good, as the Technical Questionnaire came back complete with two photos of the phenomenon. GEIPAN settled on the hypothesis of a sky-tracer, meaning a powerful searchlight aimed at the sky. Three points support it: the blue color, which is common for such devices; a confirmed cloud ceiling, shown by the witness's photo and by 7/8 oktas of cloud cover recorded on MétéoCiel, which could reflect the beam; and the movement, first fixed and then sudden and silent, which appears to match a maneuver of a ground-based searchlight. However, no public data or on-site check made it possible to locate a sky-tracer at that time, even though the Atelier des Lumières lies along the line of sight (an employee was questioned). GEIPAN classified the case as B: probable sky-tracer observation.