In the nearly two decades I’ve lived and worked in Paris, I’ve never seen it this quiet. It’s an eerie, empty quiet.

At first, it took time for people to understand what was happening, that this new coronavirus was much more than an Asian crisis. Schools here closed on March 12—and yet on the following weekend, spring was in the air, it was sunny and beautiful, and Parisians couldn’t resist going outdoors.

Then on March 16, the full meaning came clear when President Emmanuel Macron ordered the entire country to stay at home for 15 days, starting at noon the next day. That morning, a line 200 yards long formed outside my supermarket. As I photographed the line,