© Stéphane de Sakutin, AFP
In this file photo taken on October 14, 2014, former French President Valery Giscard d'Estaing is pictured during the opening of the World Nuclear Exhibition (WNE) at Le Bourget, Paris.
French prosecutors said Monday they are opening an investigation into ex-president Valery Giscard d'Estaing over allegations by a German journalist that he sexually assaulted her after an interview in 2018.

The investigation follows claims by reporter Ann-Kathrin Stracke that Giscard d'Estaing, 94, repeatedly grabbed her buttocks in his Paris office.

Giscard d'Estaing, France's oldest surviving former leader, served as president from 1974 until 1981, when he lost out on re-election to Francois Mitterrand.

Stracke, 37, told AFP last week she had filed charges against the former leader, claiming he had placed his hands on her backside three times while they posed for a photograph together in December 2018, when he was 92.

"I decided to tell my story because I think that people should know that a French former president harassed me sexually after an interview," said Stracke, a journalist for German public television WDR.

She took her case to Paris prosecutors on March 10 this year, backed by her employer which carried out an independent investigation into her claims.

Stracke said Monday she was pleased to hear of the decision, adding: "I am, of course, at the disposal of the French authorities in the context of this investigation."

Giscard d'Estaing's lawyer declined to comment.

Tried to push him away

Recalling the interview on December 18, 2018, Stracke said last week that she had asked for a photograph to be taken with Giscard d'Estaing and her colleagues after the interview.

"I was standing to his left, and while taking the photo, he put his hand on my left waist before sliding it to my backside where it stayed," said Stracke.

The same action was allegedly repeated twice — once while a new photo was being taken and another time when the former president was showing Stracke photographs of himself next to other world leaders or family members.

"I tried to push him away but I didn't manage to," she said.

To get out of what she called a "very degrading" situation, she turned to a cameraman who toppled a lampshade to divert attention while placing a chair between the former leader and the journalist.

Back at her office, she spoke about the incident to her managers.

"WDR accompanies and backs Ann-Kathrin Stracke since the incident was known, as well as when she decided to file a complaint," the television station's spokeswoman said.

Giscard d'Estaing ushered through a spree of radical reforms as president, legalising abortion, liberalising divorce and reducing the voting age to 18.

He sits today on France's Constitutional Council, the body tasked with ensuring that laws conform with the constitution.