What he refers to as "a little dispute with a cellmate" landed Mustafa, a 29-year-old Algerian drug dealer, in solitary confinement at La Sante, France's most notorious prison, for four days.
"He got angry when I switched the light off," Mustafa told me as we stood in the narrow cell with only a bed bolted to the floor and a Turkish toilet.
"He cut his arm open with a piece of glass and claimed I did it." But if he hadn't harmed the cellmate, why was he in solitary? Mustafa flexed his hands towards the wall with a strangulation gesture. "Unfortunately, when I put my hands around his neck it left a mark."
Mustafa stood in his socks on the freezing concrete. Like all prisoners in the mitard, slang for the disciplinary section, he had to leave his shoes and jacket in the corridor outside. The name tags on the doors say puni - punished. For four days, Mustafa would have no contact with any other prisoner, no access to television or his personal belongings. He would be allowed only one hour per day outside the cell, half the usual allotment. Before being sentenced to this prison within the prison, he underwent a 20-minute trial in the little mock tribunal at the entrance to the mitard, where the prison director, Mr Alain Jego, an assistant and a guard, mete out sentences of up to 45 days in solitary confinement.
The suicide rate - already high in French prisons - is seven times higher in the mitard. When prisoners get unruly, guards throw tear gas in their cells. In a four-hour guided tour through La Sante, Mr Jego admitted that the mitard "fragilises" inmates. "What do you expect us to do with prisoners who attack each other, who break everything in their cells? Prison is by definition a place of violence."
In 20 years at La Sante, the tall, thin director with the manic smile has never known such pressure. The Justice Ministry wants him to be open, but it doesn't come easily. Ten days ago, the head of La Sante's infirmary, Dr Veronique Vasseur, denounced the prison's rats and cockroaches, its rape, drug abuse, self-mutilation and suicides. Now French politicians are demanding a parliamentary inquiry, and a local official wants the massive, 133-year-old prison torn down. Dr Vasseur is supported by medical staff and the prisoners, but Mr Jego no longer wants to work with her.
Mr Jego says at least a quarter of his 1,200 prisoners are mentally ill, and another quarter are drug addicts - many of them AIDS-infected. After staff are paid, his budget leaves £2.16 per prisoner per day for food. Conditions could be improved, Mr Jego admits - if French taxpayers were willing to pay for it. The Netherlands spend four to five times as much on each prisoner as France does.
Cameras, peepholes, gates, bars and barbed wire, clanging doors, jangling keys. We are shown several model cells (minus their occupants) in the "terrorist" section where "Carlos the Jackal" screams out at night, begging for someone to talk to him. I ask to see a cell at random, on the well-founded suspicion that it will be less clean. The name of an alleged leader of the Algerian Armed Islamic Group (GIA) is on the door. He has stuffed toilet paper in the guards' peephole. A colour poster of Mecca is taped to the wall, along with verses from the Koran. Close to one-third of La Sante's prisoners are Algerian Muslims.
French-speaking Africans are kept in Block B, north African Arabs in Block C. In the latter, unpainted for decades, rust congeals on the pipes. Cobwebs shroud the upper walls. Layer upon layer of paint and plaster peel away, each more grey and dingy. A mouse runs among the wooden crates of advertising for Portuguese wine and labels for "Champony" children's softdrink, which the prisoners are paid a pittance to assemble. "Our Happy Lives", says a poster for a film in the prison auditorium.
Birami, a Senegalese drug dealer who wears the bright blue uniform of working inmates, pulls me aside. "They knew you were coming and made us start cleaning when we woke up this morning," he says. "You saw the chicken on the lunch trolleys? That's because you're here." In his cell, he shows me the food he has hoarded. "I'd starve otherwise." Prisoners must pay French supermarket prices for all but the most basic rations. Cockroaches scurry across a shelf. Birami brandishes a can of roach killer. "The rats come out at night. I beat them dead with a broom, and throw them in the waste bin."
Bouallem, Mustafa and Mo hamed, Algerians convicted of theft, are asleep. When we ask a guard to open their door, they sit up in their bunks and agree to talk to us. Bouallem scratches his back with both hands. "Everybody in La Sante itches," he says. As for Dr Vasseur's book, "We're all really happy. Everything she says is 100 per cent true. If you want a psychologist to give you drugs, they send you right away. They dope us up to keep us quiet. But if you need a dentist, you have to wait a month." In the infirmary, Dr Hugues d'Audiffret tells me that up to half of La Sante's prisoners are on tranquilisers.
To cover the peeling plaster and discourage the bugs, Bouallem, Mustafa and Mo hamed papered their cramped cell with Zineddine Zidane posters and labels from the companies they work for.
"Here is America On-Line," Mohamed announces, pulling back the sheet he uses for privacy in his lower bunk. The sides of the bed are plastered with iridescent CDs, free Internet time handed out with French newspapers. The prisoners at La Sante have no access to the Internet.
"I work for Yves Saint Laurent," the grey-bearded Mustafa laughs from the top bunk. And he hands me a tiny foil packet of "self-tanning moisturising milk with natural apricot extracts for a luminous, natural, uniform, suntan without sun."