Emmanuel Macron, the French president, is facing further embarrassment after a photograph emerged of his former aide Alexandre Benalla posing for a selfie with his gun.

Benalla is back in the headlines after Mediapart, the investigative website, this week published a picture of him pointing a pistol at a restaurant waiter during the presidential election campaign in 2017. At the time, Benalla only had permission to carry the weapon inside Macron’s La République en Marche party headquarters in Paris. The police are investigating the incident.

Mediapart (@Mediapart) En pleine présidentielle, Benalla dégaine son arme pour un selfie https://t.co/Y5BdHnE4tc

The presidential security aide was already under investigation after he was filmed apparently beating up May Day protesters while wearing a police armband. He was fired from his job after the attack was revealed in July. He denied being violent.

The selfie photo in the restaurant was taken at the end of April 2017 after Macron held a rally in Poitiers in the run-up to the second-round presidential vote between Macron and the Front National’s Marine Le Pen.

In the picture, Benalla is seen pointing his Glock pistol at the neck of an unnamed restaurant worker in Les Archives restaurant in Poitiers. Two other men stand close behind her.

Guillaume Duru, who was the manager of the restaurant at the time, said he was not present when the photograph was taken, but knew about it and advised the woman to keep quiet.

“The waitress called me during the evening and told me what happened,” Duru told La Nouvelle Republique newspaper. “She talked about a selfie. I thought it was very dangerous for the person involved, for Benalla, and that he could lose his job for doing that. I found it a bit pathetic for one of Macron’s bodyguards to do a selfie with a waitress. I told her to keep it to herself.”

Benalla, 27, had requested permission to carry a gun during the election campaign but his request was refused; it was finally approved in October 2017, five months after the election.

During questioning, as part of a parliamentary inquiry into his behaviour, Benalla told senators he possessed three Glock pistols and a Remington handgun. In an interview with Le Monde, he insisted he had not carried a gun outside the party HQ during the presidential campaign.

Benalla’s lawyer, Laurent-Franck Liénard, told AFP the selfie story had been blown out of proportion to damage his client’s reputation. “Leave him alone,” Liénard said.