We talk about crimes against humanity - I would say there comes a moment when humanity must prevail over the crime

Former justice minister Robert Badinter

The court decision means that a ruling on the lawyers' request will be taken in 18 months rather than the usual three years.

Papon is the highest-ranking French official to be convicted for crimes against humanity. As a senior civil servant in the wartime Vichy administration, he organised the deportation of some 1,500 Jews to Nazi camps.

His appeal for clemency has triggered a heated debate inside France, where a growing number of high-profile supporters - including a senior rabbi - are backing his freedom bid.

Deportation of Jews

His lawyers said they brought the appeal on the grounds that Papon's detention was "inhumane and degrading", in breach of the European Convention of Human Rights.

They also insist that keeping the former Bordeaux official behind bars would only increase public sympathy for him.

President Chirac has rejected two previous calls for clemency on health grounds.

Papon organised the sending of Jews to Nazi camps

Other opponents, notably the families of those whom Papon sent to their deaths, say that freeing him would be an insult to justice.

But supporters say Papon's continued incarceration serves no purpose.

"We talk about crimes against humanity. I would say there comes a moment when humanity must prevail over the crime," former justice minister and elder statesman Robert Badinter has said.

Other high-profile supporters include ex-Prime Minister Raymond Barre, senior Jewish leader Rabbi Gilles Bernheim and the Movement against Racism and for Friendship between Peoples (MRAP).