The former prosecution spokeswoman for the United Nations tribunal trying Yugoslav war crimes was detained by court police in the lobby on Thursday ahead of the reading of a verdict against former Bosnian Serb leader Radovan Karadzic.
It was not immediately clear why Florence Hartmann was detained on Thursday. A court spokesman did not immediately return to a call seeking a comment.
Hartmann, a French national, was convicted of contempt of court by the tribunal in 2009 for publishing confidential material from the trial of former Serbian President Slobodan Milosevic. She was initially fined 7,000 euros, but the fine was later converted to a seven-day prison sentence, which she is not believed to have served.
Hartmann was a spokeswoman for former prosecutor Carla Del Ponte.
Former Bosnian-Serb leader Radovan Karadzic, known as the "Butcher of Bosnia," is accused of 11 crimes that was listed in a 69-page indictment between the years 1992-95 in Bosnia and Herzegovina at the International Criminal Tribunal for the former Yugoslavia (ICTY).
UN judges will pronounce their verdict on Thursday in Karadzic's trial over the 1995 Srebrenica massacre, Europe's worst atrocity since World War Two.