The distinction between the informal public sphere and the institutional sphere is vital for Jürgen Habermas’ proposal related to the role of religion in the public sphere. This text questions the informal or institutional character of citizen interventions and technical concepts presented in public unconstitutionality actions. For this purpose, we analyze sentence C-355-06, focusing on those interventions and concepts with a religious content. This analysis allows us to conclude that it is necessary for the intervention space to be considered as a mixed space, since Habermas’ democratic theory requires the discussion to be comprehensive and
inclusive.