Unexplained circular mark in a garden in Jouars-Pontchartrain

Summary

Between 1988 and early 1990, three people in Jouars-Pontchartrain, Yvelines, discovered a circular mark roughly two metres across in the grass on their property. The imprint, apparently caused by flattening, remained visible for months due to a difference in regrowth. The testimony did not reach GEIPAN until 2008. With no description of any aerial object and no witnesses to the mark's formation, the case was deemed insufficient for investigation as an unidentified aerial phenomenon.