France's official UAP unit investigates a ground trace at Trans-en-Provence

No footage exists. The record is an investigation file: gendarmerie statements taken the following day, photographs of two concentric circular marks on the ground, and soil and vegetation samples collected from inside and outside the marks. Laboratory analysis reported differences between samples taken at the centre and at the edges, including changes in the plants growing there.

The witness, a gardener working on his property, told gendarmes he heard a low whistling sound and saw a small object descend into his field, rest briefly on the ground, and leave. He was the only witness. GEIPAN, the UAP unit of the French national space agency CNES, has stated the case is one of the most thoroughly documented in its archive and that it remains unexplained under its own classification system.

GEIPAN investigated through official channels and publishes the file in its searchable public archive, which makes this an officially collected case rather than an anecdote. The unit classified it in its category for cases that remain unexplained after investigation. The physical analyses were carried out by French laboratories and reported changes in the sampled material that the investigators did not attribute to a known cause. Other researchers have questioned how much the plant analysis can carry, given a single witness and one sampling visit.

There is one witness and no corroborating observation. What produced the ground marks has not been identified. Whether the reported differences in the soil and plants require an unusual cause, or could follow from ordinary variation and handling, is disputed among the scientists who have looked at the data. The object itself was never identified.