The knocking wall of La Machine: the poltergeist the gendarmes recorded

In 1973, La Machine was a town running out of time. The coal mines that built it in the Nièvre were winding down, and Le Monde had already run a piece titled "La Machine, ville morte". Miners' families lived close together in the estates. At the Cité des Minimes, two of them, the P. family and the U. couple, shared a single thin partition wall. They were not on good terms.

Monday, 5 November 1973. About nine in the evening. Dominique P., aged 11 in most accounts, was going to bed when knocks came from the wall behind his bed. His father assumed the neighbours were responsible and went next door, angry. One account describes a calm scene. The wife was shelling peas. The husband stood in the doorway. They denied everything.

The knocks came back the next evening. And the next. They were dull, repeated and rhythmic, sometimes lasting until one in the morning. They fell on a diffuse zone of 20 to 30 cm around a central point in the wall. Nothing was ever seen. This was a case of sound and touch alone.

Dominique devised a code. One knock for yes, two for no. On the recordings his voice can be heard: "Pour oui, tape une fois !" The wall answered. When he hummed or whistled, it kept the beat, through military marches and songs by Marie Laforêt. One tape reportedly catches him whistling Viens sur la montagne as the wall beats time.

It answered questions too. The commander's number of children. The strength of his brigade. The number of rounds in his magazine. "Il a répondu à des questions très personnelles que je lui ai posées," Guilbert said years later. Accounts of a horse race test differ. In one, the wall knocked 13 times when the race card listed 14. The next day, there had been one non-starter.

The family called the La Machine gendarmerie. Adjudant Bernard Guilbert arrived with a tape recorder. After about 15 quiet minutes, the knocks began, and he recorded them. His men watched the attic, the neighbours' side of the partition, the basement and the garden. They found nothing. They said they felt the shock wave through the wall itself.

Guilbert never wavered. "Je suis sûr d'une chose, il n'y avait pas de trucage, pas de supercherie." In 2015 he told France Musique: "On a vérifié, il n'y avait aucun branchement, aucun magnétophone, rien d'anormal."

The mathematician and parapsychologist Yves Lignon visited from Toulouse during the events. On Sud Radio in 2011 he was blunt: "Dans cette affaire, on peut dire qu'on a eu affaire à un cas authentique de maison hantée." Lignon noted the knocks came only when the boy was in the room. He saw them as energy released by an adolescent in revolt, what parapsychologists call recurrent spontaneous psychokinesis. He said a sect later arrived and presented Dominique as a messiah. The boy broke down and spent weeks in hospital. When he returned, the knocks had stopped.

Others suspected a hoax, by the neighbours or by Dominique himself, though the boy never confessed. Another theory held that the old mine galleries beneath the town carried small impacts made outside the house. No official conclusion has ever surfaced.

The P. family later moved south and asked to stay anonymous. Guilbert retired to Imphy. Extracts of the gendarmerie tapes survive, the sound of the knocks themselves alongside Dominique's voice. With the Enfield poltergeist a few years later, La Machine stands among the few well-known poltergeist cases caught on audio tape. Half a century on, nothing has explained the knocks.