I read the same thing after the Paris attacks. Attacks caused 137 deaths and 368 injuries. This is low compared to the Paris population (2 million in the city, 10 million in the urban area). But personally, several friends were seriously injured in the Bataclan, and many of my colleagues knew victims too. You don't have to be a direct victim to suffer from an attack. Nearly every young parisian is linked to a victim. So, no, it's not a "totally irrational" fear.