The last known survivor of the team that carried out last November's Paris terror attacks has refused to talk during questioning by anti-terror judges, with the session ending abruptly.
Salah Abdeslam's lawyer Frank Berton said his client had invoked his right to silence.
Abdeslam, 26, had said last month he wanted to explain all. Berton told reporters on Friday that Abdeslam was disturbed by the 24-hour video surveillance in his maximum-security cell, and called the practice illegal.
"He can't tolerate being watched on video 24 hours a day," Berton said. "Psychologically that makes things difficult."
Friday was the first time Abdeslam was questioned since his extradition from Belgium last month. At that point, Berton said his client wanted to talk to investigators and explain his path to radicalisation. It was unclear why the suspect changed his mind.
Abdeslam, a French citizen of Moroccan origin, was handed a half-dozen preliminary terrorism charges after his transfer on April 27 from Belgium, where he was arrested after four months on the run.
He is the only suspect still alive believed to have played a direct role in the November 13 bloodshed at a concert hall, stadium and Parisian cafes, which killed 130 people. The other attackers died in suicide bombings or under police fire.
Authorities and families of attack victims had hoped Abdeslam's testimony will shed light on how IS plotted the attacks, solve mysteries that remain about what exactly happened on November 13, and identify others who might have been involved, or support networks still hiding in the shadows.
Abdeslam's precise role in the attacks has never been clear. The Paris prosecutor has said he was equipped as a suicide bomber, but abandoned his plans and fled to Belgium, where he had grown up. Abdeslam's older brother blew himself up at a cafe during the Paris attacks.
Abdeslam was captured on March 18 at a hideout near his childhood home in Brussels' Molenbeek neighbourhood. Four days later, suicide bombers detonated their explosives in the Brussels airport and metro, killing 32 people.