From Saint-Michel-les-Portes village at the foot of the French Alps, it's impossible to see what's going on in the yoga school. The ashram, which is set on 20 hectares in the Vercors mountains south of Grenoble, is not easily accessible. To get to the Domaine du Martinet, on a misty September morning after rain, you have to descend a tortuous path, covered in cracks and rocks, for a long time, before reaching two imposing lion statues guarding the entrance.

On the grounds, crossed by a torrent of water, a large marquee and hall are dedicated to kundalini yoga. This style of yoga has become very popular and is practiced by tens of thousands of enthusiasts across yoga studios France. It claims to liberate psychic strength through long exercises of rapid breathing, yoga poses and the recitation of mantras. Sometimes, in summer, singing and shouting emerge from the bottom of the valley, according to several locals.

The place, shrouded in mystery, raises questions: What does the founder of the establishment, Jean-Louis Astoul, teach? Few people know. Better known by his spiritual names of Karta Singh or Satyavrati Yogi, the teacher asks each participant not to talk about his teachings in the outside world. The smiling, 73-year-old Astoul receives visitors on the first floor of the site's guesthouse. With a long white beard and his white hair pulled back into a topknot, he came in after his morning kundalini practice, wearing a long tunic and socks, completely dressed in white.

At his side was Prem Jot, his partner, a former German fashion designer who described herself as a pioneer of "overcycling." Now she is the yoga school's "project manager." She settled cross-legged into an armchair, eyes half-closed. She remained motionless for more than half of the two-and-a-half-hour interview. As soon as she was seated, Astoul suddenly became suspicious and held out his finger: "Who sent you? I know you've been investigating me for several months." He has every right to be on the defensive. According to the Grenoble public prosecutor's office, he is under investigation for "potential sectarian drift" and at least five alleged sexual assaults on employees and students of his ashram. On Thursday, October 19, the kundalini yoga teacher was taken into police custody. The following day, he was charged with sexual assault and undeclared labor. He has also been heard as "assisted witness" [status that can precede a formal indictment], for abuse of weakness in a context of a possible cult, according to prosecutor Eric Vaillant.

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