For the first time in a dozen years France's antiterrorist authorities are investigating an alleged terrorist plot by an 'ultra Left' group. In December nine people were arrested at various locations around France. Seven of them were subsequently placed under formal investigation on suspicion of plotting “violent action” against the forces of law and order. Five of them have been held in custody since then. Mediapart's Camille Polloni has spoken to the families and friends of some of those arrested about what they have gone through. Inevitably this new case brings with it reminders of the long-running 'Tarnac affair' in which after a decade of investigations and legal proceedings a group of left-wing activists accused of terrorist acts against French railway lines eventually saw all those charges dismissed.