`titrebDownward social mobility and its political consequences : a reconstructing of value system and political preference. `/titreb This article studies the political consequences of intergenerational downward mobility among wage-earners. The first focus of the analysis is effects of downward mobility on values and political attitudes. In this connection, analysis of Panel Électoral Français 2002 data (Cevipof-Cecop-Cidsp) brings out the strength of the « position » effect : for three out of the four dimensions studied (ethnocentrism, authoritarianism, economic liberalism), the downwardly mobile are likely to adopt the attitudes characteristic of the group they are moving into. However, in the case of social preoccupation, an « origin » effect is found, strongly suggesting an original reconstruction of the downwardly mobile’s axiological world as a whole. The second part analyzes the effects of downward trajectories on position in political space. In the framework of a three-part political space, the aforementioned original reconstruction of the value system is reflected in a particular political positioning, and for stated political preference, downward mobility has its own effect : a relatively strong attraction to the extreme right. Two hypotheses are developed to explain this result : the feeling of relative deprivation that goes with downward mobility, and the original reconstruction of social and economic discourse by the « déclassés ».