The failure to deliver justice by prosecuting the murderer of Sophie Toscan du Plantier should "always be a deep shame for us", Tánaiste Micheál Martin has said.
Ms Toscan du Plantier's body was found badly beaten outside her holiday home in Schull, West Cork, in December 1996.
Ian Bailey, who died in January at the age of 66, was the main suspect in her murder. He was convicted in absentia by a French court in 2019 but he always denied any involvement.
"Her murder, 28-years-ago, was deeply shocking, and it remains so to this very day," Mr Martin said.
"The savage attack which took her life remains seared into our consciousness and a failure to deliver justice, uphold her murderer to account, is and should always be a deep shame for us.
"The terrible anguish of her family and all who knew her was made much worse by the fact that our system proved incapable of meeting its responsibilities to Sophie."
Mr Martin said that there is "no doubt" that the case gives cause for reflection.
"It remains a reason to question whether justice is always served by the principles and procedures by which we judge these cases," he said.
"The simple fact is, we failed in our duty to find and convict a bloody murderer, and our system blocked alternative routes when others were not willing to accept our failures."
The Tánaiste said that the cumulative evidence against Mr Bailey is "overwhelming" from his own assessment.
He described Bailey as being a "violent man who had beaten his partner so badly she had to attend hospital", while saying his psychological profile was that of a "impulsive narcissist and misogynist".
"When you look at the details of this case and the scale of the evidence, it is very, very hard to understand why this evidence was not put before a jury," Mr Martin said.
He said that while the Irish justice system does have strengths, including the fact that it is independent and external pressures cannot be placed on judges, it was possible to admit it failed in Ms Toscan du Plantier's case.
Mr Martin paid tribute to both Ms Toscan du Plantier and her family, describing their three decade wait for justice.
Following Mr Martin's speech, Ms Toscan du Plantier's uncle — Jean-Pierre Gazeau — called for an inquest to be launched into her death and called on Mr Martin to support the cause.