If accidental matchmakers got Yelp reviews, Pamela Grace and Arnim Ludwig Kaiser would give five stars to the waitress who served them on Oct. 11, 2022, at Le Plaza-La Paillotte, a restaurant in Arles, France. A half-star deduction for one too many tableside visits might be justified, though.

Ms. Grace and Mr. Kaiser were both out-of-towners having dinner alone when Ms. Grace, 80, got up to leave and felt unsteady. Mr. Kaiser, 79, seated nearby at his own table, invited her to sit for a moment. “It was the first time he’d ever asked a strange woman to his table and the first time I’d ever sat down with a man I didn’t know,” Ms. Grace said.

The waitress, she said, “was watching the whole interaction with a smile on her face.”

“I think this nice young woman got a kick out of seeing this old man and this old woman who had come in alone sitting together,” Ms. Grace said.

On a first sweep by their table, the waitress reinforced a sense of compatibility by noting they had ordered the same dinner — salmon followed by a crème brûlée made with local lavender. But on a subsequent check-in she interrupted Mr. Kaiser midsentence. “She ducked in to ask if we would like anything else, and Arnim had just said, ‘My wife.’” Because of the interruption, “he never got to finish his thought.”

Ms. Grace returned to her hotel that night assuming Mr. Kaiser was “a nice, honest European man” who was happily married, she said. It wasn’t until several days later, when she was back home in Fort Greene, Brooklyn, and he in Gernsbach, Germany, that she would learn that he was a widower.

Ms. Grace, a retired adjunct professor of film studies at Brooklyn College who earned a Ph.D. in cinema studies from N.Y.U. at age 60, is a longtime member of the New York committee of Human Rights Watch. Her 2022 trip to France was for a Human Rights Watch summit meeting. She grew up in Watertown, N.Y., and graduated from Manhattanville College with a bachelor’s degree in English; She earned a master’s degree in social work from Columbia.