French authorities have called a crisis centre after rail services were disrupted across the country.
The incident affected hundreds of thousands of French people who were going to Paris for vacation and the Olympics, said outgoing Prime Minister Gabriel Attal.
Due to the disruptions, the French authorities convened a crisis headquarters, which discussed the situation with rail service, reports the BFMTV channel.
Attal called the incident a sabotage that had a "clear goal." The attackers, according to the politician, were trying to block the high-speed train network.
They partly succeeded. Hundreds of thousands of passengers were unable to get to Paris and London. Some were going to Britain for vacation or business, others were going to watch the Olympic Games.
About 25% of trains between Paris and London have been cancelled. Officials say the situation is gradually stabilising.
Paris Mayor Anne Hidalgo also called the incident sabotage. But she assured that the incident would not affect the opening ceremony of the Olympics (20:30 Moscow time).