Agathe Habyarimana is accused by the current Rwandan government of helping to plan the 1994 genocide, and has long been sought by prosecutors there.

Mrs Habyarimana, who has been living in France for several years, denies the accusations.

More than 800,000 Tutsis and moderate Hutus died in the massacres of 1994.

French officials said Mrs Habyarimana was detained in the Paris region by police executing a Rwandan-issued international arrest warrant.