PARIS — I recently discovered the secret to livening up even the dullest conversation: Introduce the topic of clutter. Everyone I meet seems to be waging a passionate, private battle against their own stuff, and they perk up as soon as you mention it.

“I don’t buy anything — no clothes, no shoes,” a woman who works in the French fashion industry told me. A New Yorker on a de-cluttering bender explained: “There’s too much in my head, there’s too much stuff in my house, too.” Another friend said that when his girlfriend got angry, she called him the clutter of her life.

Clutter isn’t a new problem, of course. But suddenly, it’s not just irritating — it’s evil. If you’re not living up to your potential, clutter is probably the culprit. Marie Kondo’s “The Life-Changing Magic of Tidying Up,” the top-ranked book on The New York Times list of self-help books, promises that, once your house is orderly, you can “pour your time and passion into what brings you the most joy, your mission in life.”

This isn’t just an American problem. Ms. Kondo’s book was a best seller in her native Japan, too, as well as in Taiwan, South Korea and Germany. (Nearly 30 translations are planned.) Karen Kingston, a British clutter expert who consults around the world, says her online courses, including an advanced class called Zero Procrastination, draw students from at least 18 countries.