After lunch they found themselves walking along the quais lining the Seine River, broad banks paved with stone and dotted here and there with trees, which were now covered with tender green leaves. They weren’t alone. The quais were popular with strollers and dog walkers; from time to time they watched a barge or tourist boat chug past. Eventually, coming to a bridge, they noticed the metal fences looked very odd, and climbed up the stone steps from the quai to investigate. Reaching the bridge, which was near Notre-Dame, they discovered the metal webbing on both sides was filled with locks, many with names and initials, sometimes even a crudely scratched heart.

“I think lovers put them here as a token of everlasting love,” said Lucy. “I bet they throw the keys into the river.”

Bill peered over the side, down into the murky water. “Down there with the rusty bikes and rotting bones . . .”

“It’s a romantic gesture,” said Lucy. “We should do it.”

“I’m surprised the city puts up with it,” said Bill, studying the thickly packed locks with a builder’s eye. “That’s quite a bit of weight. I wouldn’t be surprised if all this metal is putting stress on the bridge.”

“It seems fine,” said Lucy. “I wonder if there’s anyplace nearby that sells locks.”

“I don’t see a hardware store, but I do see Shakespeare and Company.”

Lucy followed his gaze and saw the famous English-language bookstore that had served as a temporary home to so many authors, including Hemingway and Fitzgerald. “Let’s go,” she said, forgetting about the locks.

They spent a happy hour browsing among the books, both new and used, and Bill bought himself a used copy of A Moveable Feast, the book Hemingway wrote describing his life in Paris as a young writer.

Lucy disapproved. “Hemingway was kind of a jerk, always punching people out,” she said as they wandered through the twisting, narrow streets. “And he kept leaving his wives for other women.”

“You don’t think he would have put a lock on the bridge?”

Lucy considered the matter. “Nah, he’d spend the money on a drink.”

“Good idea,” said Bill, spotting another corner café.