Since the French and Dutch “no” to the Constitutional Treaty, EU institutions have made a priority of projects relating to “participatory democracy”, “deliberation” and “Plan D”. But before these tools to “encourage the emergence of a citizens' opinion” can be mainstreamed, they must be the subject of an in-depth analysis. This policy paper offers an assessment of the first participatory experiments to take place at EU level. It is based on a seminar-assessment organised by Notre Europe and Sciences-Po in 2010.