France's eldest detainee was sentenced to 10 years in prison on Friday for having killed an 82-year-old woman who he had a crush on, but rejected his advances.

A court in the northeastern city of Reims found Marcel Guillot, a 93-year-old man nicknamed "Grandfather Marcel", guilty of "death blows on a vulnerable person with premeditation."

The body of Nicole El Dib was found in December 2011 in a stream that crossed her property near the village of Saint-Gilles in a pool of blood. She had been beaten, strangled and stabbed to death, but the killer would escape police for another five months.

A DNA analysis of blood found on a watch left on the crime scene eventually pointed the finger at Guillot, who was arrested as he began his annual vacation on an island on the French Atlantic Coast. 

He reportedly told detective she'd humiliated whom he had a crush on, and had gone to her home to punish her. 

During the trial, Guillot, who has problems hearing, repeatedly denied any wrongdoing, saying he never hit the victim who he said killed herself by slipping on a carpet and hitting a wardrobe.

"I wanted to know why she refused to see me… I don't understand, we were always good together. I did not hit her, she was my girlfriend," he told the court. But the prosecutor said the defendant had "let rip his fury."

"There is no doubt about criminal intent," the prosecutor said, blasting Guillot for expressing "no regret nor any compassion towards the person he called his friend."