Jean-Gabriel De Tarde or Gabriel Tarde was a French sociologist, criminologist and social psychologist who conceived sociology as based on small psychological interactions among individuals, the fundamental forces being imitation and innovation.
Tarde was born in Sarlat in the province of Dordogne, and he studied law in Toulouse and Paris. From 1869 to 1894 he worked as a magistrate and investigating judge in the province. In the 1880s he corresponded with representatives of the newly formed criminal anthropology, most notably the italians Enrico Ferri and Cesare Lombroso and the French psychiatrist Alexandre Lacassagne. With the latter, Tarde came to be the leading representative for a "French school" in criminology. In 1900 he was appointed professor in modern philosophy at the Collège de France. As such he was the most prominent contemporary critic of Durkheim's sociology.