Paris: France's highest constitutional body began examining a complaint on Tuesday from a Frenchman seeking a law change to allow a pardon for his father who was executed in 1957 for killing a policeman in an armed robbery.
The law in France, which abolished capital punishment in 1981, prohibits the "legal rehabilitation" of convicts who were put to death.
Gerard Fesch approached the Constitutional Council for a change in law to allow for a posthumous reprieve for his father Jacques Fesch, who became a devout Christian in jail.
Making the request all the more extraordinary is that Gerard Fesch never knew his father, having been given up by his mother shortly after he was born and growing up in foster care.
Jacques Fesch was sentenced to death on April 6, 1957, and executed on October 1 of that year, aged 27.
During a half-year on death row, he turned to religion in a dramatic repentance that senior French Catholics today deem worthy of beatification.
Patrice Spinosi, one of Gerard Fesch's lawyers, said it was "manifestly against the constitution" that a person executed could not be considered for rehabilitation when any other condemned criminal had a right to ask. He said he expected a "strong" and "humane" decision from the court.
The Council is to give its ruling on February 28.
The guillotine, a vertical, framed device that carries out executions by beheading, was the official means of capital punishment in France from the French Revolution until the country's last execution in September 1977.
"What I want is that history does not just remember the guillotine but that every person can repent and become better," Gerard Fesch, 65, said about his campaign.
Gerard Fesch was 40 when he discovered who his father was, after a friend pointed out striking details in a magazine feature about Jacques Fesch's execution.
"I could have very well stopped there. But I saw that he was interested in my existence," he said, insisting that his father was "not a hooligan".
Just before being executed, Jacques Fesch wrote a letter to his "son Gerard" saying, "May he know that even though he could not be my son my law, he is in the flesh and his name is engraved into my heart."
His paternity was legally recognised in 2007, and the next year Gerard took Fesch as his surname.
The aim is not to "rejudge him" but to find a kind of a pardon and place "another stone in the fight against the death penalty," said Gerard Fesch.