PARIS — When people used to ask me what I missed about America, I would say, “The optimism.” I grew up in the land of hope, then moved to one whose catchphrases are “It’s not possible” and “Hell is other people.” I walked around Paris feeling conspicuously chipper.

But lately I’ve had a kind of emotional whiplash. France is starting to seem like an upbeat, can-do country, while Americans are less sure that everything will be O.K.

Cynicism has deep roots in France. In the 18th century, Voltaire mocked optimists for their naïveté and celebrated pessimists for their lucidity. He’s still part of the national curriculum for French eighth-graders, and the râleur — the dissatisfied, grumpy whiner — remains a national archetype. Among intellectuals, if you say that everything is going badly, “everyone says, ‘Look how intelligent he is,’” explained Frédéric Lenoir, author of “Happiness: A Philosopher’s Guide.” Since I’ve lived here, polls have regularly shown that the French are more pessimistic about their country’s future than people in Afghanistan and Iraq.

The French haven’t become magically cheerful, but there’s a creeping sense that hope isn’t idiotic, and life can actually improve. As is common with a new president, there was a jump in optimism after Emmanuel Macron was elected last year. But this time, optimism has remained strong, and in January it hit an eight-year high.