The sole surviving suspect from the attacks on Paris in November wants two live video cameras removed from his prison cell, his lawyer said.
Salah Abdeslam's lawyer claimed that the constant surveillance risked damaging him psychologically.
Abdeslam was confined to France's high-security Fleury-Merogis prison after a months-long manhunt that followed the gun and bomb attacks that left 130 people dead in the French capital on November 13.
Unusually stringent security measures imposed on the 26-year-old include round-the-clock video surveillance from two infrared-enabled cameras located inside his cell.
His lawyer, Frank Berton, has appealed to an administrative tribunal in the Parisian suburb of Versailles to have the devices removed.
"He's spending all his time talking about cameras. Cameras, cameras, cameras," Mr Berton told journalists outside the tribunal following the hearing.
"It's an obsession for him."
Speaking earlier to a three-member panel inside the tribunal, Mr Berton argued that the surveillance - purportedly imposed to keep Abdeslam from killing himself - was breaching his privacy and risked damaging him mentally.
"Medical professionals say it's worse than anything else" and almost unheard-of internationally, Mr Berton told the panel. "In the US, to my knowledge, this doesn't exist."
Government representative Fabrice Verriele said the surveillance was "necessary and proportionate".
The circumstances of Abdeslam's confinement are important given his potential ability to divulge key information about the November assault and those behind it.
The controversy over the cameras has become a political issue, with Justice Minister Jean-Jacques Urvoas, who ordered the surveillance, saying he would propose a new law to put the monitoring on a firmer legal footing if the tribunal rules against him on Friday.
Mr Berton said he understands why some have little sympathy for his client but insisted Abdeslam deserves to have his rights respected.
"Justice is not vengeance," he said.