A damp towel hangs from a barred window, a fan churns the muggy air: Inmates at the overcrowded Villepinte prison outside Paris say enduring a heatwave that has stifled France in recent days in cramped cells is "inhumane". French MP Clémentine Autain witnessed the conditions during an unannounced visit on Friday afternoon to the penitentiary in the Seine-Saint-Denis Paris suburb, accompanied by AFP. Inmates told the left-wing parliamentarian of the impacts of waiting out the heatwave that saw record-breaking May temperatures in France in recent days in cells measuring nine square metres (100 square feet). "At night, it's hot, and mosquitoes get in even though I try to make a sort of mosquito net with my laundry bag," said one teenaged detainee, adding that "tensions rise more quickly in the heat". As Autain visited, another young prisoner was taken back to his cell in a wheelchair after collapsing in the yard. Read moreFrench prisons: A ticking time bomb Minors have individual cells, but in the rest of the building it is increasingly common for three detainees to share. The Villepinte prison has an official capacity of 703, but at the time of Autain's visit it held 1,332 inmates. The overcrowding forces nearly 200 prisoners to sleep on mattresses on the floor or on makeshift bed frames. On Thursday, the UN Subcommittee on Prevention of Torture (SPT) raised the alarm over "severe prison overcrowding" in France, warning conditions in some facilities "may violate the fundamental rights" of detainees and "may constitute inhuman or degrading treatment under international law". As of May 1, a new record was set, with 88,654 inmates in France, according to the monthly justice ministry figures. In one cell, a 20-year-old inmate indicated his makeshift bed, overturned shelf and bottles of water. "I've been set up like this for a year," he said. 'Crammed into a cell' The men passed the hours watching a 24-hour news channel reporting extensively on the impact of the heatwave that has smashed temperature records across Europe, beyond the peeling prison cell walls. "We're only entitled to three showers a week: Monday, Wednesday, Friday," one inmate told the MP, who appeared taken aback. Limited access to the shower block, where mould riddles the ceilings and walls, is a result of overcrowding. The prisoner does not deny the usefulness of detention, but said "at least they should put us in better conditions". "(Nicolas) Sarkozy in prison, I don't get the feeling he had the same conditions as you", said Autain, referring to the former French president who spent several weeks in prison late last year.