Sighting in Rantigny, September 29, 2016

A witness was in their garden in the evening when they noticed fluffy, cotton-like masses spinning rapidly in the cloudy sky, without making any sound. They called their partner and a neighbour, who saw the same thing. The whole display rotated counterclockwise. It stayed visible for about three hours before vanishing behind the clouds. It was not bright enough to be photographed. Two witness accounts were collected.

According to the investigation, the cause was most likely laser beams from a nightclub or from a festive or exceptional event, reflected off the cloud layer or the fine rain, both of which were present that evening. The witness themselves sometimes saw a beam rising from the ground toward the part of the sky where the strange discs had been earlier, and neighbours mentioned spotlights. Depending on the state of the air, one can see the patterns on this natural screen, the beams alone, or both, much like in a smoky cinema. A laser's range varies greatly with atmospheric conditions and can reach tens of kilometres, which can make the phenomenon fleeting, even exceptional, far from the source.

GEIPAN did not identify the source of the beam, but it has several similar cases that were identified. It therefore classed this case as B: probably sky rose or light spots.