An “ultra-left militant” was arrested in north-west France on Sunday after being found behaving suspiciously near a railway site, according to police sources quoted by French media.
Officers who searched the man’s car found keys to technical premises, pliers, a set of universal keys and literature “linked to the ultra-left”.
The 28-year-old suspect is currently being questioned by police in the city of Rouen, French media said.
There is no indication that the man has links with the people responsible for Friday’s suspected co-ordinated arson attack on railway lines ahead of the opening ceremony for the Paris Olympic Games.
The acts of sabotage paralysed high-speed TGV lines running to and from Paris and heavily disrupted travel in France.
On Monday morning, France’s Minister of the Interior Gerald Darmanin said that a “number of profiles of people who could have committed these very deliberate, very targeted acts of sabotage” had been identified.
He added that the methods employed were “traditional” of the ultra-left and said there was “likely a political claim” behind the sabotage.
“The question is whether they were manipulated or is it for their own account,” Mr Darmanin said, adding that investigators were making good progress and would find those responsible.
Although he stopped short of saying the saboteurs had accomplices within France’s national rail operator SNCF, Mr Darmanin noted the locations of the arson attacks were “extremely specific”
“It was obviously extremely well targeted, it wasn’t done randomly, and it affected three major lines,” he added.
Mr Darmanin also said that around 50 people were arrested ahead of the Olympics who, alongside others – thought to number around 150 – had “wanted to carry out either sabotage or radical protests in Paris during the first events of the Olympic Games”.
Alongside the damage to the train lines, French media also reported that fiber optic cables were found cut in six locations across France overnight Sunday into Monday, causing some isolated outages.
It is still unclear at this stage whether there are any links between the vandalism on the telecoms installations and the sabotage on the rail network last week, which affected an estimated 250,000 passengers on Friday and hundreds of thousands more over the weekend.
No group has yet claimed responsibility for either incident. One security source suggested in French media last week that the arson attacks bore all the hallmarks of the extreme left.
Transport minister Patrice Vergriete said on Monday that trains services were back up and running as normal after teams worked around the clock over the weekend to fix the damage.
He added that “considerable means”, including drones and police helicopters, were deployed to strengthen the security of the thousands of kilometres that make up France’s railway network.
Mr Vergriete also said that the acts of sabotage will likely have cost several million euros.