I just found myself in the middle of an anti-terrorism operation in Paris - here's what the initial moments of confusion were like

PARIS, France - Paris is on edge.

After three major attacks in France and several smaller incidents over the past two years, terrorism has become a regular part of the conversation here - on TV, on the radio, and in the streets.

In the past two weeks alone, authorities say they have thwarted two attempted attacks.

Perhaps it is no surprise then that shoppers in central Paris called the police on Saturday afternoon when they thought they heard an explosion on Rue St. Denis near Rue Étienne Marcel.

People crowded into a church on the cobblestone shopping street to hide. In the commotion, police thought it might have been a hostage situation.*

It was a deemed a false alarm, but not before more than a hundred officers, including elite units, were called to the scene, according to Reuters.

I happened to be walking by that church at the time, and within a matter of minutes, found myself in the heart of a major security operation, as police who were holding protective shields and wearing bulletproof gear advanced on the scene, shouting at passersby to get away.

I was impressed by how quickly authorities reacted to the situation, but what perhaps surprised me the most was how many people stuck around to watch events unfold. To be sure, some ran away as soon as police arrived, but hordes of others stood by gawking - and even demanding that police tell them what was going on.

Here's what it's like to find yourself in the middle of a major police operation in the heart of Paris.

*This version of events is according to several police officers on the scene with whom I spoke. Some local French media are reporting that the phone call was a hoax.