The European Court of Human Rights on Thursday ordered France to pay thousands of euros in damages to dozens of inmates after ruling that authorities had not taken sufficient measures to end prison overcrowding.

The case was filed by 32 inmates from six prisons including one of France's largest at Fresnes, outside Paris, which holds 2,500 people -- nearly double the number of beds at the site.

"The court considered that the personal space allocated to most of the applicants had fallen below the required minimum standard of three square meters (32 square feet) throughout their period of detention," it said in a statement.

It also criticised a "lack of privacy in using the toilets" at the six facilities.

France has about 70,800 people behind bars at 188 penitentiaries according to official figures from October 2019. Official capacity is 61,065, for an occupancy rate of 116 percent.

Nearly 1,500 mattresses are placed on the floor because no beds are available.

Conditions in French prisons have long been an embarrassment for the state, with President Emmanuel Macron himself once describing them as "disgraceful".

An official report on conditions at the Fresnes prison in 2016 found it to be infested with rats, with prisoners sleeping three to a 10-square-metre cell.

It also criticised a shortage of personnel, a widespread problem that was a major complaint by guards during two weeks of nationwide strikes in January 2018.

Macron has promised to create space for 7,000 additional prisoners by the end of his term in 2022, and has implemented a series of sentencing changes aimed at finding alternatives to jail time.

A cell at the Fresnes prison near Paris, one of France's largest, which holds some 2,500 people -- nearly double the number of beds at the site.
A cell at the Fresnes prison near Paris, one of France's largest, which holds some 2,500 people -- nearly double the number of beds at the site. AFP / Philippe LOPEZ

But the rights court said "overcrowding in prisons and the dilapidated state of some prisons acted as a bar to the full and immediate cessation of serious breaches of fundamental rights".

It recommended the adoption of "general measures aimed at eliminating overcrowding and improving the material conditions of detention," and ordered France to pay the plaintiffs damages of 4,000 to 25,000 euros ($4,400-$27,500) each.

Patrice Spinosi, a lawyer with France's International Prisons Observatory (OIP), which coordinated the prisoners' cases, called the decision "a huge victory".

He urged the government to undertake a "global rethink on sentencing" in order to combat the chronic overcrowding, instead of simply building new prisons.

"An overcrowded facility is one that lacks sufficient activities and work for inmates, that lacks equipment, and one where access to care is difficult," said Nicolas Ferran, the OIP's head of litigation.

France's justice ministry said it had "taken note" of the court's ruling, adding that it had steadily increased budgets for prison upkeep in recent years.

Beyond the 7,000 additional spots being created for 2022, it said it aims to have an additional 8,000 in place by 2027.

The ministry also expects to thin prison populations with the phasing in of recent court reforms, including the elimination of sentences of under one month and automatic probation or public service for people ordered to serve six months or fewer in jail.

The European court has also faulted other European countries for prison overcrowding, including Hungary, Italy and Romania.