The widow of the Earl of Shaftesbury has been found guilty of arranging his murder.
Jamila M'Barek's brother Mohammed was also convicted of carrying out the premeditated murder for her.
They were both jailed for 25 years after being found guilty by 10-1 majorities by the jury in Nice, in the south of France.
The badly-decomposed body of Anthony Ashley-Cooper, the 10th Earl of Shaftesbury, was found in a remote ravine in the foothills of the Alps in April 2005, five months after he went missing from his £130-a-night hotel on the French Riviera.
Jean-Louis Moreau, the state prosecutor, said Jamila M'Barek, 45, a former nightclub hostess who became Lord Shaftesbury's third wife in 2002, paid her brother 150,000 euros (£105,000) to murder him.
She wanted her estranged husband dead so that he could not divorce her and deny her the chance to inherit valuable properties in France and Ireland.
Her 43-year-old brother killed the 66-year-old peer during a drunken row in November 2004, but claimed throughout his trial that he strangled him "accidentally".
Nicholas Ashley-Cooper, the late peer's second son and now the 12th Earl of Shaftesbury, said he did not believe Ms M'Barek ever loved his father.
He said: "I believe that she is manipulative and scheming, and ultimately an evil person," adding: "You caused the death of an innocent man and you caused my family a lifetime of hurt."
The 29-year-old, who sat in court throughout the four-day hearing with his mother Christina Cassell and aunt Lady Frances Ashley-Cooper, rejected the apology Mohammed offered the family in court earlier this week, saying: "I do not forgive him, and will never forgive him as long as he does not admit to the murder of my father."
