Prisoners in France's southern island of Corsica are in for a treat next month when they will be allowed out of jail to cycle a Tour de France stage three weeks ahead of the professionals.

The local government announced Friday that an undisclosed number of heavily-guarded prisoners who have been training since April will take to the steep hills of the island to replicate the Bastia-Ajaccio stage on June 10.

They will take on "a challenge that will see them brave the hills of the Vizzavona pass and cross Corsica from north to south," the prefecture said in a statement.

Not willing to let the prisoners out of their sights a team of fit prison guards will join the prisoners peloton, and will be tasked to make sure no chains are broken.

The prisoners – and guards – have already been training on roads and on home-trainers in the jails to "develop the physical and mental qualities necessary to achieve this sporting feat," it added.

The 100th edition of the world's most famous bicycle race kicks off on June 29 in Corsica – which has never before welcomed the cycling event.

The Mediterranean island of Corsica is known as the island of beauty but after a dozens of gangland killings in recent years it is also commonly referred to as the unofficial "Murder capital of Europe".