14 May 2022, about 03:10 local; approximately eight seconds
Outcome: Open (Unresolved). GEIPAN retained D in its February 2026 report after radar enquiries, a field reconstruction and consideration of aircraft and visual-perception hypotheses. The reported rectangle and apparent background distortion remain unverified by a recording.
Eight seconds from a balcony
A Montluel resident reported watching a dark rectangular appearance travel from west to east between hills before dawn on 14 May 2022. The account describes no running lights or trail, together with a faint halo and an apparent alteration of the clouds behind it.
The witness likened that last impression to images associated with black holes. That comparison describes appearance; it is not evidence of a black hole, gravitational lensing or an exotic propulsion system. The investigated question is what could have produced the reported view.
The enquiry’s chronology
GEIPAN received the completed questionnaire on 17 May, requested radar information in July, and conducted a field visit on 1 July 2023. The report now available is dated 13 February 2026. These are different stages of one 2022 case, not separate incidents.
The fieldwork documented the view and the hills used as reference points. Calculations explored dimensions and speeds compatible with the witness’s estimated angular size and the supposed passage behind terrain. Such calculations are conditional on that interpretation of the scene. They do not provide an independently measured range to an object.
Aircraft, afterimages and sleep-related suggestions
No matching aircraft was established in the radar material used by the investigators. The report also considered an afterimage following screen use and a sleep-related perceptual experience. It found those explanations insufficient against the reconstructed sequence and the details of the account.
Those conclusions should not be overstated. The file contains one witness and no photograph or video of the appearance. An assessment of an optical hypothesis against a remembered sequence is different from recording the observer’s vision or conducting a clinical experiment. The report does not supply a new medical test performed during the event.
The meaning of the calculated minimum size
GEIPAN’s analysis gives a minimum length of about 15 metres and speed of about 130 kilometres per hour under its reconstructed geometry. Those figures depend on the reported angular extent and passage behind a hill, including allowances for estimation error. They are not radar-derived dimensions or a calibrated camera measurement.
The observer’s reference to cloud deformation creates a second interpretative problem: whether a dark foreground shape, a perceived change in cloud appearance and a physical disturbance of cloud are the same thing. Only the first-person account is available here. It would be premature to use the calculated scale to prove the physical reality of the reported background effect.
Why the case remains unresolved
GEIPAN retained category D after its analysis. UKPX follows that documented outcome as Open (Unresolved), without adopting the witness’s physical interpretation of the reported background effect. There is no claim here that all conceivable ordinary causes have been disproved.
The useful surviving material is a prompt questionnaire, a detailed reconstruction and a reasoned discussion of alternatives. Better evidence of the disappearance behind the hill would particularly strengthen or weaken the distance-based calculations. Until then, the geometry helps frame the question but cannot by itself establish the nature, origin or technology of what was perceived.
Location and map reference
Montluel, Ain, France. Broad commune reference from the French government geographic API; not the witness home, precise observation position or object location. This listing does not advertise access to private property.
Sources and review
CNES–GEIPAN official case record and the original investigation report. Current case page;27-page report pp 1–4 and 25–27; chronology, conditional geometry and final optical-hypothesis discussion. Radar enquiry does not justify a radar-detection tag. Sources and current classification checked 13 November 2026. The incident date above is distinct from the later investigation and archive-update dates.