A former doctor from Rwanda has gone on trial in France on charges of genocide and crimes against humanity.

Sosthene Munyemana was a 29-year-old gynaecologist living in the south of Rwanda at the time of the 1994 genocide in which 800,000 people were killed.

He has lived in France for 29 years and is accused of organising torture and killings.

In 1995, a year after the Rwandan genocide, a complaint was filed against Mr Munyemana in the city of Bordeaux.

It took French prosecutors 28 years to bring the case to trial.

The key to an office in a place called Tumba will strongly feature during his trial in Paris.

Mr Munyemana, who admits he had the key, said people from the Tutsi population sought refuge in the office, with his defence lawyer arguing he worked to prevent the genocide.

But prosecutors say he locked them inside in inhumane conditions before they were taken away to be killed.

One thing that both sides in the case agree on is that it is unacceptable it has taken so many years for it to come to court.

Mr Munyemana, who denies the charges, faces life in prison if convicted.

The genocide was sparked by the death of Rwandan President Juvenal Habyarimana when his plane was shot down above Kigali airport on 6 April.

Mr Habyarimana was from Rwanda's Hutu ethnic majority, and while exactly who killed the president has not been established, the presidential guard in Rwanda's capital Kigali immediately initiated a campaign of retribution.

Leaders of the political opposition were murdered, and almost immediately, the slaughter of Tutsis and moderate Hutus began.

Within hours, recruits were dispatched all over the country to carry out a wave of slaughter.

Between April and June 1994 an estimated 800,000 Rwandans were killed in the space of 100 days.