Sighting in Paris, August 25, 2019

One morning, a couple on their terrace watched a point of light in the sky for nearly 30 minutes, its appearance changing over time. The two witnesses followed its movements with a telescope and binoculars, and took photos and videos with their mobile phone. GEIPAN rated the case's consistency as very good: two witnesses described their observation in careful detail, and photos and videos exist.

The investigation pointed to an assembly of helium-filled Mylar balloons tied together. Several elements support this: the shape seen through the telescope resembled such an assembly; the brightness to the naked eye matched Mylar balloons, which strongly reflect sunlight; and the trajectory, a slow, steady climb along an arc, fit weak winds whose direction varied a great deal between 250 and 2,750 m altitude. The sudden disappearance may have been the balloons bursting, as the expanding helium put increasing pressure on them at height, although no data demonstrates this.

The photos and videos are of little use: sharpness fluctuates and focus is lost, because a smartphone cannot focus well on an object with such a small angular size, and zooming makes this worse. No balloon release on that day was found in the media or on social networks. GEIPAN therefore put forward a hypothesis consistent with the testimony, without formal proof, and classified the case as B: probable observation of an assembly of Mylar balloons.