Trust is a core component of the freedom and security of citizens, making relationships work more cohesively and efficiently. But it is fragile. Undermining trust raises transaction costs, weakens social cohesion, and ultimately reduces the freedom of citizens and impoverishes society (Arrow, 1972). Dishonesty introduces a major threat on trust and the ubiquity of deception is a major concern of modern society. Big scandals have been revealed in finance and sports but ordinary deception is also widespread (cheating in exams, fare dodging, CV inflation, sabotage at work, etc.). Dishonesty often results from abusing information asymmetries. Governments and organizations spend considerable resources to detect dishonesty and implement coercive measures, which may be detrimental on freedom and social welfare. FELIS’s ambition is to contribute to a better understanding of the determinants of deceptive behavior in order to improve the deterrence of dishonesty and promote the security of citizens in a free world. FELIS seeks to understand when people are more, or less, likely to act honestly and follow the moral course of action instead of serving their strict self-interest at the others’ expense. It aims at undertaking the standard economics-of-crime approach comparing the expected monetary benefits and costs of fraudulent actions by incorporating social, moral, emotional and psychological factors in economic decision-making. It will explore various mechanisms designed to fight against dishonesty while preserving the freedom of citizens. The key challenge of FELIS is to provide a characterization of 1) strategies used to deceive oneself and others; 2) the links between deception and asymmetric information; 3) the deterrence effect of both uncertainty of audits and sanctions; 4) how social networks form and convey peer effects leading to norms of honesty or dishonesty; 5) how trust is affected by dishonesty. This defines five scientific Work Packages. Work Package 1 investigates how individuals lie while trying to maintain their self-concept of honesty, by exploring how the distance between the truth and a lie affects decisions and can be manipulated. Work Package 2 studies the link between deception and the exploitation of asymmetric information, by exploring strategic truth-telling as part of a greedy deceptive strategy. Work Package 3 examines both the deterrence effect of information disclosure on the occurrence of crackdowns and whether there exists optimal sanctions discouraging dishonesty while avoiding criminality traps. Work Package 4 focuses on the social dimension of deception, notably the formation of social networks and peer effects in networks. Work Package 5 studies how to restore trust after it has been destroyed by the dishonest behavior. The ground-breaking nature and potential impact of FELIS is to go substantially beyond the current state of the art by offering a unique combination of game theory, experimental economics and psychology to better understand the causes and consequences of dishonesty in order to better identify efficient modes of deterrence that preserve the freedom of individuals. It combines theoretical modeling based on behavioral economics and experimental methods (laboratory experiments, lab-in-the-field experiments, neuroeconomics) to study the motivation of individuals to behave dis/honestly. The Consortium involves behavioral economists and experts in the physiological and neural analysis of emotions from GATE (CNRS, University of Lyon), the CORTEX laboratory of excellence, and CREM (CNRS, University of Rennes). It includes international partners: experts in the econometrics of networks and tax evasion at Laval University in Quebec, a psychologist specialized in the analysis of lying behavior at the Ben Gurion University, and behavioral economists from the University of Amsterdam and the National Research University Higher School of Economics in Moscow.