France's Constitutional Council on Friday struck down a law penalizing the repeated viewing of extremist websites that show killings or attempted killings with up to two years in jail.
The law was not "necessary, appropriate and proportionate," the council ruled, noting that authorities already had a panoply of measures enabling them to combat terrorism and online extremism.
The law, passed by parliament last year against the advice of the government, exempted "good faith" use of such websites and their use by journalists, researchers and those prosecuting offences.
But the Constitutional Council held that while it was not clear what was meant by "good faith," the law criminalized habitual viewing of such websites regardless of whether the offender had any intention of committing an act of terrorism.
That could lead to doubts about the legality of using certain online services, and as a result about the legality of using the internet to seek information, the Council said.
Extremist groups, notably the Islamic State organization which claimed responsibility for deadly terrorist attacks in Paris in 2015 and Nice in 2016, have made considerable use of the internet in spreading their propaganda.
Islamic State in particular became notorious for the videos it published online, using the shock value of brutal executions of prisoners in order to gain an audience for its threats to local and international enemies.