The blood of Princess Diana's chauffeur on the night she died will be re-examined, French judges have ruled.
Henri Paul's parents believe he was not drunk at the time of the crash
Henri Paul, who also died, was blamed for the crash after blood tests showed he was over the legal limit of alcohol.
But Mr Paul's parents, Jean and Giselle, believe the blood tested did not belong to their son.
The decision by the French court of appeal overrules the investigating judge, who had dismissed two previous requests for new toxicology reports.
The ruling is unconnected to the inquiry by the Metropolitan Police Commissioner Sir John Stevens into the princess's death, which will report back to a London coroner.
A spokesman for the public prosecutor's office in Paris confirmed the appeal court's decision.
"Three magistrates, who are above the trial judge, looked at the case. They found that the judge's decision wasn't right," he said.
He added the appeal was only concerned with the issue of Mr Paul's blood.
Mr Al Fayed believes there is a conspiracy surrounding the crash
"His family think that he didn't drink too much. They thought that it wasn't their son's blood," the spokesman said.
Blood tests carried out in the days following the crash suggested Mr Paul was three-times over the legal alcohol limit.
Mr Paul's parents had asked the investigating judge, Corinne Goetzmann, to re-examine the blood in 2002.
They were joined by Harrod's owner Mohammed Al Fayed, whose son Dodi was also killed in the Paris crash.
But Ms Goetzmann dismissed their requests in 2003.
'Major step forward'
Mr Al Fayed, who believes his son and Princess Diana were murdered, welcomed that appeal court's decision.
He said: "It is a major step forward in getting to the truth.
"Henri Paul was used as a scapegoat to conceal a murder.
"It was not his blood that was tested. It was a cover-up
orchestrated by the security services."
On 29 June the French court of appeal ruled Judge Goetzmann was wrong to deny the request to re-examine the blood.
They demanded on Thursday that toxicology tests be repeated.
This investigation is one of several into the fatal crash.
Royal Coroner Michael Burgess opened and adjourned an inquest into Diana's death in January this year.