TV5 Monde has returned to the air after the large-scale cyber attack that took the Francophone network off air around the world.

The French security agency Anssi has sent a team of 13 staff to TV5’s headquarters to carry out a root and branch audit of the channel’s information systems. Viewers are expected to see little difference on air.

Channel director Yves Bigot told AFP that the attack was totally unprecedented in the history of television.

The attack on Wednesday, thought to have been undertaken by persons sympathetic to Islamic State took down TV5’s broadcast systems, and its website presence.

EBU president Jean-Paul Philippot condemned the cyber-attack in the strongest terms. “Hacking into the output in this way threatens the values of freedom of expression and a pluralistic media which help form the basis of public service broadcasting, a system built on diversity and a considered interpretation of the world and its values.”

The Upper Audiovisual council of French media regulator CSA also condemned the action as a “serious attack on freedom of communication of a key channel in the Francophone world”.