The author, who works as a city policy consultant in Paris, proposes a new approach to urban design. The author suggests the concept of the “15-minute city, 30-minute territory.” This means that a multi-center city should be built where six social functions, including residential, work, healthcare, education, culture, and living supplies, are provided within a 15-minute living radius. The author’s philosophy is to make all living facilities accessible within 15 minutes on foot, by bicycle, or other means. This approach is being used in urban projects worldwide, including France. The author’s solution to modern society’s problems, such as the climate crisis, pandemics, resource depletion, and social conflicts, is leading lifestyle and urban space changes. This suggests a significant implication for the domestic situation in Korea, where there is a continuous concentration of population in Seoul, and regional cities are becoming desolate. The article concludes with a notice that the copyright belongs to Seoul Economy and that unauthorized reproduction and redistribution are prohibited.