This document was reproduced in the ufological litterature long ago.
They are the first two photographs taken by the gendarmerie squad of Genlis, of a trace in a field with Marliens, allotted to the landing of an UFO on May 10, 1967.
It is said that a machine not identified would have been located by the military radar of Creil, and the study of the ground under the traces of the UFO showed depressions not very ordinary and the presence of a mauve powder. According to later analyses, the powder would have consisted of silica crystals having undergone a beginning of fusion with 1500 minimum °C.
More probably, the trace was caused by lightning or ball lightning.
PHOTOGRAPH #1 : GENERAL AERIAL VIEW.
The comparison with the van give an idea of the size of the inprint.
PHOTOGRAPH #2 : AERIAL VIEW OF THE INPRINT AS IT WAS DISCOVERED (Before any excavation or modification).