Journal article: The purpose of this article is to determine a distribution along a political axis of the candidates for the 2012 French presidential election on the basis of the opinions of voters, rather than on a priori ideological positions. To do so, experimental data from a voting experiment on approval voting are used. The obtained endogenous axis representative of the political landscape corresponds to a fairly standard left-right axis. However, a more precise analysis of the behavior of voters questions the unimodality assumption of political preferences usually associated with this structure. Voters often simultaneously approve candidates on both sides of the political spectrum but without supporting intermediary candidates on the axis; besides, this attitude is more common among men than women.