On October 21, 1982, a biologist — identified in GEPAN's official case files as Mr. N. — was at his home in Nancy, France, when he observed an unidentified object stationary above his garden at approximately five in the afternoon. The encounter lasted approximately twenty minutes during which he was able to observe the object in detail and take note of its behavior. This case subsequently became one of the most scientifically significant in GEPAN's entire archive because of the biological effects the object left on a plant in the garden.
The object was described as roughly disc-shaped with a central dome, approximately one and a half meters in diameter, hovering without support at approximately one meter above the ground. It emitted no sound. Its surface appeared metallic and smooth. The witness observed it for the entire twenty-minute period before it rose vertically and departed. He reported feeling weak and disoriented after the encounter and noted that his arms felt temporarily paralyzed while the object was present.
GEPAN investigators arrived at the site relatively quickly after the report and took samples of an amaranth plant (genus Amaranthus) that had been growing in the garden directly beneath the object's position. The plant was analyzed by a laboratory at the Institut National de la Recherche Agronomique (INRA), and the results were remarkable. The plant showed changes to its biochemistry consistent with accelerated aging — the chlorophyll content of the affected leaves had been transformed in a pattern that laboratory analysis associated with extended sun exposure or specific electromagnetic radiation, but compressed into a fraction of the time that natural processes would require.
The INRA analysis, published in GEPAN Technical Note 16 in 1983, found that the amaranth leaves showed a 30–50% reduction in chlorophyll content relative to control samples taken from the same plant in areas not directly under the object. The pattern of damage was consistent with exposure to a strong electromagnetic or ionizing radiation source and was directional — the most affected tissues were those facing directly upward toward the object's position.
GEPAN's Technical Note 16 is one of the most cited documents in UAP scientific literature precisely because it represents a case where a reported encounter produced measurable, laboratory-verified biological effects analyzed by an independent government scientific institution with no stake in the UAP question. The amaranth plant sample remains the most thoroughly analyzed physical trace from a European UAP case.