David Chavalarias (ISC-PIF): CNRS Research Director, HDR, Centre d’Analyses de Mathématiques Sociales (CAMS), Ecole des Hautes Etudes en Sciences Sociales (EHESS). David Chavalarias is the Director of the Paris IdF Complex Systems Institute (http://iscpif.fr) and permanent CNRS researcher at the Center of Social Analysis and Mathematics (EHESS). Normalien and PhD of the Ecole Polytechnique (Paris), his highly interdisciplinary work is situated at the crossroads between the cognitive sciences and the science of complex systems, which he mobilizes for the study of collective intelligence and social dynamics, both from the point of view of the modeling and the reconstruction of social dynamics from large scale Web data. Among other, he has worked on the effect on the large scale deployment of ITC and recommendation systems on our collective dynamics, on the issue of opinion manipulation through online astroturfing as well on the analysis of political activism on social media.