In France, as in most western countries, immigrants are widely believed to be responsible for increased crime rates and media and political discussions often connect them with "insecurity". These concerns actually relate to two different situations: crimes committed by foreigners and crimes committed by those born in France to immigrant parents and thus holding French citizenship. This article, a critical survey of studies dealing with these situations, looks at both administrative data and qualitative and quantitative research. While police statistics cannot be used to measure the criminality of immigrants, they can be used to distinguish crimes committed by immigrants from those committed by citizens with immigrant backgrounds, such as the theft and physical violence classically seen among the poorest part of the population. Sociological research makes it possible to show that those born to immigrant parents of African origin are oveerrepresented among delinquents in some locations but that this is not uniformly true throughout the country. This finding points to the need to look at the effect of local contexts from a perspective that is both sociological and psycho-sociological.