Prisons are overcrowded in nearly half of the countries across western and eastern Europe, where there are in some cases 150 prisoners for 100 places, a report published Friday showed.
Twenty of the 47 countries in the Council of Europe have more prisoners than places available, according to the report published by the pan-European organisation which compiled statistics for 2011.
Serbia led with 157.6 prisoners for 100 places, followed by Greece with 151.7 prisoners and Italy with 147 prisoners, the report said.
France had 113.4 prisoners for 100 places, Belgium had 127.2 prisoners and Hungary had 138.2 prisoners.
The authors of the report warned that each country set different criteria for prisoner capacity, adding comparisons may be misleading.
"Overcrowding is a problem in half of the European penitentiary administrations," according to a statement accompanying the Council of Europe Penal Statistics survey.
The report compiled by University of Lausanne researchers Marcelo F. Aebi and Natalia Delgrande said Council of Europe member countries counted a total of 1.86 million inmates in their prisons in 2011, or 154 prisoners for 100,000 inhabitants.
But there are large disparities between countries.
There are fewer than 50 prisoners per 100,000 inhabitants in countries like Iceland, while the proportion climbs to 200 in some eastern European countries.
The highest rates are in Russia, which has 546.1 prisoners for 100,000 inhabitants, followed by Georgia with 541.2, and Azerbaijan with 417.
In contrast, France has 111.3 prisoner per 100,000 people, and Germany has 86.8.
France meanwhile has a high suicide rate among its prison population, according to the council.
There were 95 suicides in 2010, or 15.5 suicides for 10,000 inmates, against an average of 6.7 for the council's member countries.
The suicide rate in the Netherlands was 17 per 10,000 inmates, and Belgium with 16.7. The rate in Germany was 8.1, while that in Italy was 8.0.