The Trans-en-Provence Case is one of the rare cases where a UFO is said to have left physical evidence, in the form of burnt residue from a field. The event took place on January 8, 1981, outside the town of Trans-en-Provence in the French département of Var. It has been described as "perhaps the most completely and carefully documented sighting of all time".
Event details 
The case began on January 8, 1981 at 5pm. Renato Nicolaï, a fifty-five year-old farmer, heard a strange whistling sound while performing agricultural work on his property. He then saw a saucer-shaped object about eight feet in diameter land about 50 yards (46 m) away at a lower elevation.
According to the witness, "The device had the shape of two saucers, one inverted on top of the other. It must have measured about 1.5 meters in height. It was the color of lead. This device had a ridge all the way around its circumference. Under the machine I saw two kinds of pieces as it was lifting off. They could be reactors or feet. There were also two other circles which looked like trapdoors. The two reactors, or feet, extended about 20 cm below the body of the machine."
The local gendarmerie were notified of the event the following day by Mr. Nicolaï directly on the advices of his neighbor's wife, Mrs Morin. The gendarmerie proceeded to interview Mr. Nicolaï, take photos of the scene, and collect soil and plant samples from the field. The case was later sent to GEIPAN - or GEPAN (Groupe d'Étude des Phénomènes Aérospatiaux Non-identifiés) as it was known at that time - for review.
Analysis of evidence 
GEPAN analysis noted that the ground had been compressed by a mechanical pressure of about 4 or 5 tons, and heated to between 300 and 600 degrees Celsius. Trace amounts of phosphate and zinc were found in the sample material, and analysis of resident alfalfa near the landing site showed chlorophyll levels between 30 and 50 percent lower than expected.
Impressions and explanations 
However, GEPAN's investigation focused on conventional explanations, such as atmospheric or terrain causes of a terrestrial nature. But despite a joint investigation by GEPAN and the gendarmerie which lasted for two years no plausible explanation was found.
Skeptical analysis 
The police report said that the trace, which appeared on an active road, looked like one made by the tire of a car. This explanation was dismissed by GEPAN because of the sole witness saying otherwise. The physical trace shown on the picture is not a perfect circle, in fact there are two more-or-less semicircles crossing over each other. Also, a circular shape does not coincide with the description of the UFO made by Mr. Nikolaï. In a recent interview for French television, Mr. Nikolaï confirmed that there were vehicles passing by on the road at the time of the sighting.
The GEPAN came very late on the field, after the French gendarmerie, other ufologists and curious people, so the physical trace could simply have been altered in its chemical composition by the people walking on it.
See also 
- BreitBart.com: France opens secret UFO files covering 50 years
- Wilson, Jim (May 2001). "When UFOs Land". Popular Mechanics 178 (5): 66.
- National Investigations Committee On Aerial Phenomena: UFO Casebook:1981
- UFO Evidence: Renato Nicolai; Trans en Provence, France
- UFO Skeptic.org: UFO Case 4: The Trans-en-Provence Case
- Rossoni, D., Maillot, E., & Déguillaume, E. (2007). Les ovnis du CNES – 30 ans d’études officielles. www.book-e-book.com. (extracts from the book). Critical skeptical investigations of GEPAN's work.
- Figuet, M. (Ed.) (1995). L’affaire de Trans-en-Provence. Dompierre-les-Ormes, SERPAN.
- Trans-en-Provence Case - The Temporal Doorway
- Trans-en-Provence Case - UFO Evidence
- Trans-en-Provence Case - Centre National D'etude Spatiales
- (French) Skeptical explanation of this case, by Éric Maillot