A court in Paris has sentenced prominent Islam scholar Tariq Ramadan to 18 years in jail for raping three women, two years after he was given a jail term for a separate rape offence in Switzerland.

The French rape case unfolded in 2017, when two of the three women came forward during the Me Too campaign against sexual abuse and harassment.

Ramadan, a 63-year-old former professor of Islamic studies at St Antony's College in Oxford, did not attend the trial in Paris, although he has always denied the charges.

His lawyers said he was being treated in the Swiss city of Geneva for multiple sclerosis and condemned the trial as a farce.

Judge Corinne Goetzmann told the court that a warrant had been issued for Ramadan's arrest, however Switzerland does not have an extradition treaty with its neighbour.

Ramadan is also facing a permanent ban from French territory.

The court ruled that the 18-year jail term was justified by the "extreme seriousness of the acts",

"Consenting to sex does not imply consenting to any sexual act whatsoever," the judge said.

Leaving court, one of the three women involved in the case, Henda Ayari, told reporters that the judges had believed her, and she spoke of "nine years of suffering and struggle" since she had first come forward to make a complaint.

She told reporters on Wednesday that she had been thinking about all the other victims: "of the victims who had the courage to file a complaint like me, but also of those who could not summon up the strength, and those who had withdrawn their complaint because of threats and reprisals."

The second woman to come forward in France accused Ramadan of raping in her in a hotel in Lyon in 2009, whereas the Swiss case involved a woman who said he had raped her in a Geneva hotel in 2008.

Meanwhile, Tariq Ramadan has himself reacted to the sentence, calling for a "new trial, a trial with both parties present".

"I will not let this decision stand," he told Le Parisien newspaper. Insisting that it was his health that had stopped him from coming to Paris, Ramadan said if he had not wanted to attend, he would have not have assembled a legal team.

Tariq Ramadan is the grandson of Hassan al-Banna, who founded the Muslim Brotherhood.

He has long said the allegations against him are part of a campaign of slander. He told Le Parisien that he was the victim of a political bid "to remove a Muslim intellectual".

It is difficult to see how a second trial could take place without him agreeing to pre-trial detention in France, seeing that he is now subject to an arrest warrant.