Sighting in Borée, August 5, 2020

Around 7 p.m., four people hiking on Mont Mézenc suddenly noticed a bright object floating in the air that seemed to rotate on itself. They described it as a big silvery-white moon, or a big bubble. Only one of the four later reported the sighting. This witness took several photographs while the object moved silently over the landscape until it vanished into the sky, and also filmed a short video showing it heading south-southeast.

The photos, the video and the detailed account made the case a strong one and made it possible to reach a conclusion. GEIPAN identified a novelty Mylar balloon, possibly shaped like a letter (Q or O) or a number (0), released or lost not far from the witnesses. Three points support this. First, the letter shape is visible in one of the photographs, and the aluminized skin of this type of balloon at times strongly reflects sunlight, producing the flashes seen with the naked eye and in the images. Second, measurements made with the IPACO software are consistent with a balloon 0.80 to 1 m in size, about 215–320 m from the witnesses in the first part of the observation and about 1,870–2,300 m in the second, within the limits of theoretical visual acuity. Third, the object's movement, initially slow and uncertain (rotations, changes of course) under the influence of the terrain at low altitude, became steadier and straighter, carried by a southerly wind. The case was classed A.