With the economic and social changes in Europe at the end of the sixteenth century and the formation and consolidation of an urban network throughout the continent, questions such as poverty, sanitation, and hygiene began to pose acute problems in the cities of the age. A new school of thought, known in Spain as Ciencia de Policía and in the Mediterranean area as Policy Science, proposed solutions for these problems and tested them through practical interventions inside the urban setting. In this article the author compares the work of two thinkers: Cristóbal Pérez de Herrera, a Spaniard, and Nicolas Delamare, a Frenchman. Writing in the late sixteenth and early seventeenth centuries, Pérez de Herrera examined the organization of Madrid, the newly founded (though still not firmly established) capital of Spain. Delamare based his study on the Paris of the early eighteenth century. The author stresses the coincidences in some of the ideas of both thinkers and shows how their writings begin to embody a new idea of the city, many aspects of which have survived until the present day.