Notre-Dame Suicide
Police seal off Notre-Dame de Paris cathedral after Dominque Venner's suicide (Twitter)

A political row has been triggered in France by the public suicide of a 78-year-old far-right author and historian.

Dominique Venner shot himself through the mouth in front of the main altar of Notre-Dame de Paris.

He had placed a letter on the altar of the 850-year-old cathedral which was evacuated after his suicide. Police have not disclosed the contents of the letter and the reasons behind Venner's act were not clear.

Before going to the cathedral, Venner posted on his blog a damning critique of the same-sex marriage bill recently approved by the French parliament and called for "spectacular and symbolic actions [to] awaken consciences".

"New spectacular and symbolic actions are needed to wake up the sleepwalkers and shake the anaesthetised consciousness," Venner wrote. "We are entering a time when acts must follow words."

Far-right politician Marine Le Pen, a vocal critic of the same-sex marriage bill pushed by president Francois Hollande, praised Venner and described his suicide as a political act.

"All our respect to Dominique Venner, whose last and deeply political gesture has been an attempt to awaken the people of France," Le Pen, president of the Front National (FN) party, tweeted.

Nicolas Gougain, spokesman for LGBT French umbrella group Inter-LGBT, told Le Figaro that Venner's suicide was "a desperate, regrettable and very marginal act".

A former paratrooper, Venner was a member of the Secret Army Organisation (OAS), which sought to keep Algeria under French control and in the early 1960s and tried to assassinate former president Charles de Gaulle.

Venner was about to publish a new book, his editor, Pierre-Guillaume de Roux, told AFP.

"I do not believe the suicide is linked to the [gay] marriage issue. It goes far beyond that," de Roux said.