Fibre optic networks are 'sabotaged' across France - as police arrest ultra-left activist over arson attacks that sparked travel chaos on opening day of the Olympics

Fibre optic networks have been 'sabotaged' causing telecoms network outages across France, according to authorities, who have slammed the 'cowardly and irresponsible' attacks.

It comes after coordinated arson attacks paralysed high-speed train services in the country on Friday, hours before the Olympics opening ceremony, disrupting travel for hundreds of thousands of people.

An ultra-left activist was arrested at a railway site yesterday, police said today, with investigators looking into whether the man belongs to an 'anti-Olympics' movement.

The man was detained at Oissel in northern France on Sunday and had access keys to SNCF technical premises, tools and literature linked to the ultra-left, said a source.

The latest alleged acts of vandalism have hit fibre optic installations in six areas of France, including near Paris, where the games are largely being hosted.

Pedestrians walk past a French telecommunications and mobile network operator company SFR shop (file image)

Charred cables near a railway line in Courtalain after reports of 'arson' attacks on rail infrastructure on Friday

The network suffered isolated outages after being hit by acts of vandalism overnight, affecting some fixed and mobile services, France's junior minister for digital matters Marina Ferrari said on X.

'I condemn in the strongest terms these cowardly and irresponsible acts,' she said, adding that teams are working to fully restore telecoms operations.

Cables were cut in electrical cabinets belonging to telephone operators SFR, Bouygues and Free, Le Parisien reports, with other networks' users also impacted by the damage.

The report said that infrastructure in southern France, the Meuse region near Luxembourg and the Oise area near Paris had been vandalised. 

The French capital is said to have not been affected by the attacks as it stands.

There has so far been no claim of responsibility and and the number of people affected is not yet known. 

SNCF employees and French gendarmes inspect the scene of a suspected attack on the high speed railway network at Croiselles, northern France on July 26, 2024

A relay antenna was vandalised on Friday, depriving 2,000 homes of internet in Haute-Garonne, on the outskirts of Toulouse, BFMTV reports.

A group called 'No JO' (No Olympics) claimed responsibility for the fire, with one of their tags reportedly found at the scene.

SFR and Bouygues did not immediately respond to requests for comment.