The symmetry could not be more jarring. A Parisian year that began with the bloodshed and chaos of the terrorist attacks at the satirical newspaper Charlie Hebdo and later at a Jewish grocery now had an even deadlier coda: With events still fluid and exact details unclear, the authorities said more than 100 people had been killed in a series of attacks across Paris. And dozens of people were taken hostage at a Parisian theater.

The urgent, bleating screech of sirens filled the evening air as police cruisers raced through the streets, uncertain if more mayhem was to come. Taxis ferried people home without charge as the police advised residents to stay inside. Ambulances screamed down the boulevards, as a stunned and confused French capital was again left to wonder: Why us? Once again?