The Procedure for Institutional Compatibility Assessment (PICA) has been developed in the EU-project SEAMLESS-IF as a formalized methodology to assess ex-ante the compatibility between policy options and different institutional contexts (Theesfeld et al., 2008). In 2007 and 2008, PICA was applied to the implementation of the policy option 'EU Nitrate Directive' in the regions of Auvergne and Midi-Pyrénées in France. Additionally, interactions with policy experts as one important group of end-users of PICA were tested in order to define their preferred modes of interaction. This paper presents the results of the application of PICA to the implementation of the EU-Nitrate Directive in Auvergne and Midi-Pyrénées. The contribution of the tool to integrated ex-ante policy assessment within SEAMLESS-IF (S-IF) is highlighted by the combination of the PICA statements and the results of the ex-ante assessment of the EU Nitrate Directive carried out by the other SEAMLESS models in Midi-Pyrénées. Further, the implications of the empirical applications for methodological improvement of PICA is discussed Finally, the testing activities provide insights with regard to the use of PICA from the point of view of the future 'integrative modeler' running the tool as well as from the perspective of policy experts.