Social demand for Sustainable agriculture and multifunctionality of agriculture since the 2003 CAP reform, leads agricultural systems to be more friendly for the environment. In such a context, research has to work on the conception of environmental friendly agricultural systems. In East of France, a research team is prototyping two complementary mixed crop-dairy systems aiming to respect the environment and to produce milk and crops. Two organic multi-objective prototypes are being built based on (i) respect of land natural properties (ii) use of low external inputs and (iii) limitation of the exchanges between systems at a local scale. Prototyping that kind of systems requires a multi-attribute approach using different methods. Experimentation at farming system level combined to modelling might suit well that purpose.