Agnel, winner of two gold medals at London 2012, in the 200 metres freestyle and the 4x100m free relay, has denied coercion with the girl who was aged 13 at the time of the incident when he was 24.

Prosecutor Edwige Roux-Morizot revealed that the 29-year-old "recognises the materiality of the alleged facts" but she said he did not have "the feeling that there was coercion".

"If the facts constitute rape or sexual assault, it is because there is a significant age difference," Roux-Morizot said.

Roux-Morizot alleged the events took place in 2016 in several locations, including Spain, Thailand and Brazil.

Agnel was arrested in Paris last Thursday (December 9) and faced preliminary charges last Saturday (December 11), with the case now sent to Mulhouse.

In France, an adult cannot have consensual sex with somebody under 15 years old.

Earlier this year, the French Parliament adopted legislation that characterises sex with a child under the age of 15 as rape and punishable by up to 20 years in jail.

The investigation was launched after a swimmer who trained with Agnel in Mulhouse from 2014 until 2016 filed a lawsuit.

L’Équipe newspaper claimed that several swimmers, current and retired, have already been questioned as part of the investigation.

Roxana Maracineanu, France’s Minister of Sport and the country’s first-ever world champion in swimming when she won the world title in the 200m backstroke in 1998, has spoken of her shock at Agnel’s arrest.

"I personally know the person who lodged the complaint, and you can imagine that this affects me," Maracineanu said.

"It is a process that must follow its course.

"The girl’s complaint is in the hands of the justice system and must proceed to the end.

"You know that this is a very important subject for me at the national level and is a fight that we are carrying out at the European level."

Earlier this year, Maracineanu created a platform for athletes to report adults who have abused them.

Last year, she also led months of hearings after 400 French coaches, teachers and other individuals were suspected of sexual abuse or helping to cover it up.

Agnel anchored the French team to a silver in the 800m freestyle relay at London 2012 and was a double gold medallist at the 2013 World Championships in Barcelona in the 200m freestyle and 400m freestyle relay.

Agnel is also currently the world record holder in the men’s short course 400m freestyle in 3min 32.25sec.

At the 2016 Olympic Games in Rio de Janeiro, Agnel failed to go past the heats of the 200m freestyle and announced his retirement shortly afterwards.

He worked as a television commentator for French television at the re-arranged Olympic Games in Tokyo earlier this year.