One of the most spectacular murders in France is reopened after three decades.
The then convicted and now pardoned Omar Raddad (59) managed to get the judiciary to re-investigate the case so that a court could possibly establish his innocence on appeal.
The Paris Court of Cassation announced on Thursday.
"That honors the judiciary, the fight is not over yet," said Raddad's lawyer Sylvie Noachovitch.
The authorities can now start another investigation, which can take a few months.
It's all about analyzing blood traces using the very latest in DNA technology.
When the bloodied corpse of the rich widow Ghislaine Marchal (65) was found in the boiler room of her villa on the Côte d'Azur in June 1991, it was written in blood on the whitewashed cellar door: "Omar killed me".
It didn't take the police long to look.
Omar Raddad, the Moroccan gardener, was arrested four days later and later convicted of murder.
His lawyer spoke of a miscarriage of justice and serious investigative errors.
Strange traces of blood at the crime scene
It is true that the blood on the inscription actually came from the dead woman - but it has not been proven whether she wrote the sentence herself.
Later blood tests also showed that a man other than Raddad must have been in the cellar at the time of the crime: In addition to the widow's blood, traces of strange blood were found on the door.
Even the motive for the crime, the gardener's debts, did not convince the lawyer at the time.
Raddad showed no injuries when he was arrested.
No traces of blood were found on the woman's clothing.
Because the family had the widow's body cremated unusually quickly, any subsequent search for clues was impossible.
It remained unclear why the fingernails of the dead were not examined for traces of blood. In this way it could have been proven that the woman actually wrote the accusing sentence. And it also remained completely unclear how the woman who had been wounded by a knife found the strength before her death to write the words on the door with her own blood.
The then President Jacques Chirac released Raddad part of his imprisonment as a pardon; the Moroccan was released in 1998 after more than seven years in prison.
A first attempt at resumption failed in 2002. Now he wants to have his innocence established again.
Lawyer Noachovitch relies on another evaluation of the blood traces, in which DNA material from four men was detected.
And this was accordingly there during the crime - and not afterwards, for example by the investigators deployed at the crime scene.