Ian Bailey is unlikely to be extradited to France even if he is found guilty of the voluntary homicide of Sophie Toscan du Plantier.
Legal sources have confirmed a 2012 Supreme Court ruling refusing a European arrest warrant for Mr Bailey would be a major legal impediment to any further attempt to have him extradited, even if he was convicted of the killing.
“It’s difficult to see how the French would succeed without a change in Irish legislation,” one legal source told the Irish Examiner.
“There are different judges on the court than there were in 2012 but it’s very rare that a Supreme Court would go against an earlier ruling by the same court.
"So irrespective of any verdict, it’s unlikely Mr Bailey would be extradited.”
One aspect of the law on which the 2012 ruling was based has changed.
Among the grounds for refusing Mr Bailey’s extradition was that it would involve surrendering a citizen of a third country — Mr Bailey is a native of the UK — to another European state.
Since then, the Government here has changed that law to include “Irish residents”.
That alone is not seen as crucial in challenging the Supreme Court’s ruling.
The trial of Mr Bailey for the voluntary homicide of Ms Toscan du Plantier in West Cork in 1996 is due to begin this afternoon in Court d’Assises in Paris.
Mr Bailey will not be in attendance but the trial will still go ahead following a near decade-long investigation by a succession of French magistrates.
A spokesperson for the French courts has confirmed a verdict will be delivered on Friday.
Since the original murder investigation, the DPP has examined the Garda file on Mr Bailey at least four times and on each occasion ruled he did not have a case to answer.
The evidence at the trial opening today in Paris is expected to differ little from that assembled by the gardaí in the original investigation.
Mr Bailey’s solicitor Frank Buttimer has stated that he believes the court will find his client, who has always protested his innocence, guilty this week.
But he labelled the Paris trial as a “show trial”.
Summons have been to over a dozen witnesses based in Ireland but it is understood to be unlikely that any of them will travel for the trial.