Complex sentence: He was also the professor of Economics at the École des Hautes Études en Sciences Sociales in Paris, and founded and directed the Département et laboratoire d’Economie Théorique et Appliquée (DELTA), a research unit in theoretical and applied economics.
Split into simpler sentences: He was also the professor of Economics at the École des Hautes Études en Sciences Sociales in Paris. There he founded and directed the Département et Laboratoire d’Economie Théorique et Appliquée (DELTA), a research unit in theoretical and applied economics.