Thousands of people had to be evacuated because of three bombs planted in a tourist resort and on a high-speed rail line in the French Basque country.
An anonymous caller said that five explosive devices had been left at locations in the region.
Searches turned up three bombs, which the police called crude, homemade devices. They were defused.
No bombs were found in three of the places named in the warning call, but one was discovered in another location.
Jean Espilondo, the Mayor of Anglet, one of the towns targeted, complained that visitors are “being taken in hostage over minor political demands that have no chance of being fulfilled.” He added: “How dare they disrupt people’s lives and holidays.”
No one has claimed responsibility for the bombs, but they bear the hallmarks of an obscure French-based Basque separatist group which has targetted estate agents, tourist sites and a police station in the past.