Sighting in Blois, July 23, 1965

The report was filed long after the events, concerning an observation made at around 6 p.m. Several witnesses saw an object in the evening sky that looked metallic and triangular. It stayed motionless and reflected the sunlight strongly. The witness had worked out the object's altitude, and the investigation found that calculation to be sound.

According to GEIPAN, all of these features fit a tetrahedral stratospheric weather balloon. The bright, metallic look is typical of such balloons. Apparent immobility is not unusual either: they float at very high altitude, up to 40 km, so their movement looks extremely slow, and winds at that height vary a great deal. A balloon of this kind can reflect sunlight until about 40 minutes after sunset, which matches the sighting.

The investigation also noted that the planet Venus was shining brightly in the west shortly after sunset that evening. The witnesses did not mention it, which is surprising, but it was much farther west and lower in the sky than the object they observed. GEIPAN classified the case as B: probable sighting of a stratospheric balloon.