A Swiss woman has asked her country's legal system to act against Ramadan, a well-known figure in France who was suspended as a professor of contemporary Islamic studies by Britain's Oxford University in November.
The 55-year-old, a Swiss-Egyptian citizen who is the grandson of the Muslim Brothers movement, was charged with rape in Paris in February, following accusations by two women.
He denies the charges.
The new accusations come from a woman who has converted to Islam says Ramadan raped her and held her against her will in a hotel in Geneva in 2008, according to the Tribune de Genève newspaper.
In 13 pages of testimony she says she looked to him for support when she was going throught difficulties with her family and started corresponding with him after meeting him at a book signing in Geneva.
Ramadan invited her to meet for coffee but then persuaded her to go to his hotel room, where he raped her and kept her prisoner for several hours.
She says she was too frightened to make a legal complaint at the time.