Sighting in Paris, September 19, 2024

Shortly before 10:30, the witness was waiting for a meeting in a room on the 6th floor of a building. From the window, they were photographing the Eiffel Tower and the La Défense district in the distance, under a clear sky. At 10:27 they took a first picture, then a second one 2 to 5 seconds later, using a x10 optical zoom. Enlarging the second image, they noticed a shape between the Eiffel Tower and the La Défense towers. It was absent from the first photo, and they could not find it when looking directly out of the window right afterwards. They stopped observing around 10:30, when colleagues arrived.

Lit by the sun, the shape was fairly flat and seemed to be two-coloured, yellow underneath and black on top. The witness put it at 2 to 8 km away and several metres across, while acknowledging it could be closer and smaller. Flightradar24 showed no aircraft that could explain it, and the planes photographed around 12:12 looked nothing like it.

GEIPAN considered the case well documented, with a detailed description and photos. The hypothesis retained was a bird crossing the camera's field quickly: the observation was indirect, the shape was missing from the first photo, and an object moving rapidly in front of the lens, even at a very short exposure, is stretched along its direction of motion and has its black diluted towards grey. A great tit, which is yellow and black, small, and present in Paris, would fit. A radiometric study with IPACO placed the object between the lens and the Eiffel Tower, most likely nearer the lens, and in any case neither at the level of La Défense nor at 2 to 8 km. With a rooftop reference point 92 m away, the measured angular length of about 0.12° gives roughly 18.5 cm, of which a third is motion blur; the remaining 0.08° or so matches a 11 to 14 cm great tit at 80 to 100 m. The speed derived, 25 to 32 km/h, is also consistent. The case was classified B: probable photographic artefact (bird).