IRISH people living in Paris say the "mournful atmosphere" in the city is like that in New York after September 11 or the 7/7 London bombings.
Dubliner Michael Collins lives less than half-a-kilometre from the Charlie Hebdo magazine offices where the terrorists gunned down 12 people including two police officers.
The Travelmedia.ie managing director said Parisians are concerned about future attacks that could claim more innocent lives, particularly as the two gunmen were still on the run, and after the shooting dead of a female police officer yesterday in a separate incident.
"It was shock yesterday, but it is fear today," he said, referring to the ongoing worry last night that the killers would strike again.
"People realise that these two gunmen are on the loose. Now that there has also been what seemed to be a copycat incident where an officer was killed, people are nervous and fearful.
"There is no explanation for what happened, and it has made the mood and atmosphere very sombre. Everybody will be tense until these two guys are caught."
Oliver Farry, a journalist from Sligo who lives within a mile of the magazine's office, said he is "very wary" about using the city's public transport as there are fears of follow-up attacks.
He said the attacks brought back the horror of a similar incident that happened in his workplace more than a year ago and the large-scale terror attacks of the last 14 years.
"This personally reminds me of a tragedy we had in late 2013 when two colleagues from Radio France Internationale were kidnapped and murdered in Mali," he said.
"There is the same air of mournfulness around the workplace. It is like a small scale 9/11, though I don't expect it to have near the same impact. It is probably more like the Madrid or London attacks."
Mr Farry said every media outlet in Paris is being guarded by "a strong military presence" as a response to Wednesday's attacks.
Gary White, from Galway, works five blocks from the scene of the magazine attack and said he is in "complete shock" that the victims were gunned down in what he described as one of the city's "nicest neighbourhoods".
Mr White said the death of the female police officer yesterday is "worrying" because of its random nature.
"There has been no explanation as to why this happened at all. Clearly someone was inspired by Wednesday's attack, which is even more worrying," the freelance translator said.