LYON, France (AFP) — A French court on Monday sentenced a mayor to four years in jail for blackmailing a political rival with a secretly filmed sex tape involving a male sex worker.

Gael Perdriau, who has been mayor of the eastern industrial city of Saint-Etienne since 2014, throughout the trial had denied ordering the recording of a video involving his former deputy, Gilles Artigues, a Roman Catholic who had spoken out against gay marriage.

But a court in the eastern city of Lyon found the 53-year-old guilty of blackmail, criminal conspiracy and diverting public funds, handing him four years behind bars — as well as another suspended — and a five-year ban from public office, effective immediately.

Perdriau was “entirely guilty”, the presiding judge, Brigitte Vernay, said.

During the trial, prosecutors had argued that Perdriau commissioned the sex tape filmed in a hotel room in early 2015 to ensure Artigues’ loyalty, warning he would release it if his deputy broke ranks.

“He was the one with his finger on the nuclear button,” prosecutor Audrey Quey told the court, describing the mayor as the “decision-maker”.

The court also handed prison sentences to three co-defendants, including the mayor’s former chief of staff and another deputy, who admitted to setting up the trap.

After the ruling, Perdriau insisted he was innocent and vowed to appeal.

But Artigues in 2017 secretly recorded a conversation with Perdriau, in which the mayor can be heard telling him he has a “USB stick” full of compromising images and threatening to release them.

Artigues told the court the result was him being paralysed in city hall meetings.

“I was like a puppet,” he said. “They put me there, and I smiled.”

The former deputy — who testified that he had suffered suicidal thoughts — welcomed Monday’s verdict.

“Today, I think I will be able to rebuild my life,” he said, surrounded by family members.