Apropos the history of human rights in France, one spontaneously thinks of the French Revolution and then of left-wing activists, particularly socialists. Their opponents, the Catholics, normally considered to be right wing and usually opposed to socialism, appear as a counterpoint. This article argues that some Catholics, especially those who referred to themselves as ‘social Catholics’, also contributed to the adoption of certain rights, particularly social rights, in France in unexpected and paradoxical ways. Their contribution was made through their social activities, visible in their organizations’ archives more than through their discourse. Social Catholics spoke little of ‘rights’. Yet paradoxically, discourses about ‘duties’ can lead to the defence of rights, especially through the practice of social surveys and the importance of social ‘facts’. Examples are taken from the history of the Ligue Sociale d’Acheteurs, the Union Féminine Civique et Sociale and other French Catholic organizations such as the Secrétariats sociaux.