Understanding the evolution of economic activities during the development of large cities is one of the important tasks of social scientists，But this research process is full of challenges，Because under normal circumstances，It is not easy to obtain comprehensive historical data。Recent，Julie Gravier, a researcher at the Historical Research Center of the French Institute of Advanced Studies in Social Sciences, and Marc Barthelemy, scientific research director of the Institute of Theoretical Physics of the French Commission for Atomic Energy and Alternative Energies, discussed the 1829- Changes in economic activity in bet365 sports betting app in 1907 are analyzed，In order to gain a more comprehensive understanding of the bet365 sports betting app history of Paris。Relevant research results have been published in "Nature·City" magazine。

Gravel and Barthelemy exploited a newly released city directory dataset，This dataset covers individuals in Paris from 1829 to 1907、Businessman、Enterprise、Large amounts of data from organizations and important institutions, etc.。Involving about 1 million economic activity entries，Provides valuable historical insights for studying bet365 sports betting app and the evolution of economic activities。The most important thing is，Paris experienced many major events during this period，For example, the urban transformation and urbanization process of Paris from 1853 to 1870、Franco-Prussian War、Paris Commune Movement, etc.。

Contemporary scholars’ research on the dynamics of urban economic activities usually only covers a short time frame，Varies from a few years to a few decades。In comparison，The scope of Gravel and Barthelemy’s research spans nearly a century，Provides new insights into the way Paris’ bet365 sports betting app and economic activity evolve。

Gravel and Barthelemy pointed out that Paris in the 19th century was an example，Every activity in the city evolves for different reasons，Can be classified according to different dynamic and scaling categories。Some activities seem to arise naturally with the growth of cities，Regarded as an intrinsic factor in bet365 sports betting app。These activities meet the basic needs of residents，simultaneously，The number of activities changes as the population grows。In simple terms，There is a roughly linear relationship between the number of food stores and changes in population，The relationship between administrative and educational needs and population follows the optimization logic。

Gravel and Barthelemy stated in the text，A number of activities that together form the core of bet365 sports betting app，And some specific activities determine the specific appearance of the city。These findings suggest，Economic activity and changes in population size are not exactly consistent。In addition，While certain activities are vital to bet365 sports betting app，But other activities also play a key role in urban innovation。The study of the history of Paris as a city should be placed in a broader context，Because it was the largest city in France at the time。Urban scaling law helps explain the relationship between city size and economic activity，When the scaling index is greater than 1，Suggests urban innovation is in its early stages；When the scaling index is less than 1，Indicates that bet365 sports betting app has become relatively mature。

　The typological research method proposed in this study can be extended to the study of other cities，Used to analyze different characteristics of different bet365 sports betting app stages。Anyway，Gravel and Barthelemy’s research provides new insights into the diverse roles of economic activity in shaping the development of large cities。

(Zhao Qi/compiler)