On January 8, 1981, farmer Renato Nicolaï observed a disc-shaped object land briefly in his field near Trans-en-Provence, France. French government agency GEPAN collected soil samples within 24 hours and concluded ground had been compressed by 4-5 tons of pressure and heated to 300-600°C.

GEPAN's Technical Note No. 16 (published March 1983) documented alfalfa plants near the landing site with chlorophyll levels 30-50% below normal, an effect graded across distance from the center mark. Popular Mechanics later called it 'perhaps the most completely and carefully documented sighting of all time.' GEPAN classified the case type D (unexplained with physical effects).