1. Focus on the place of Citizen Science and Participatory Action Research in environmental engineering

This first section provides a brief overview of the current state of Participatory Action Research (PAR), Citizen Science (CS) and their implications for what might be termed "environmental engineering". The great heterogeneity of PAR and CS practices makes the exercise of an exhaustive synthesis perilous, but it does aim to clarify the fundamental differences between PAR and CS, without seeking to confine these terms in too arbitrary a fashion, bearing in mind that the lexical field is far from stabilized and that it is possible to speak just as much of participatory sciences integrating both PAR and CS. The article draws heavily on the approach developed by the Groupe de recherche (GDR) PARCS (Participatory Action Research and Citizen Sciences). The objectives of the GDR PARCS include