Democratization is quiet a difficult issue, from both a methodological and theoretical point of view, especially when international comparisons are undertaken. Must one consider this process like the diffusion of a good, or focus on competition between groups for access? The indicators and the results will differ, depending on the perspective used. European comparisons show that, if a majority of opening access to school, less numerous are those which have tried to act more directly upon the inequalities produced by its operation. France has chosen the openess strategy with some delay, one factor being the persisting tracks within lower secondary school. But this still characterised by stronger social inequalities than countries such as Britain or Sweden. However, France has less inequalities at the tertiary level, due to the impressive expansion at this level. Across the board, openness, way a priori simple to equalise, goes along with some important problems.