Oxford University professor Tariq Ramadan has been charged with two counts of rape by a French judge and ordered to remain in custody in France.
The 55-year old, a senior research fellow in contemporary Islamic studies at St Anthony's College, was brought in for questioning on Wednesday, and has now been brought before three magistrates, a move which suggests that he is facing an extensive investigation, according to judicial sources.
In the full investigation beginning this week, these magistrates will put together a case and establish whether he must stand trial.
In the three months since the allegations were made, police have been conducting investigations, interviewing people close to Ramadan and his accusers and examining email and social media exchanges between them.
In October of last year, the author and feminist activist Henda Ayari, who heads the women's organisation Les Libératrices, filed a complaint with French prosecutors, alleging rape, sexual violence, intimidation and harassment by Ramadan. She claims she was assaulted by him after he invited her to his hotel room in Paris in 2012.
Later, the second accuser, a 42 year-old woman, alleged that Ramadan raped her in the Hilton hotel in the French city of Lyon in 2009, subjecting her to "very brutal scenes of sexual violence".
He strongly denies any wrongdoing, saying he is the victim of "a campaign of slander clearly orchestrated by my longtime adversaries", and is suing Ayari.
On Thursday, the second woman – using the pseudonym "Christelle" – repeated her allegations in court, and said that Ramadan has a small scar on his groin, which she would not have noticed had she not been in intimate contact with him.
Ramadan has presented investigators with Facebook conversations which he says show Ayari making explicit advances on him, and which date from 2014, two years after the alleged rape.
The decision to charge Ramadan was welcomed by Ayari's lawyer, who said: "If there are other victims in France or elsewhere, they now know that the justice system will respond to what has happened to them".
Christelle's lawyer, Eric Morain, said that the charges were "an important step" after a "painstaking three-month investigation, 48 hours of police questioning and a confrontation with my client".