Even if academics and practitioners identify coopetition as a winning strategy, a coopetition relationship appear to be difficult to sustain. Coopetition is relied to be a paradoxical and unstable interfirm relationship related with tensions. Academic works begun to study the causes and nature of tension in coopetition relationship but little is known about the way those tension is managed. The aim of this paper is to investigate, via in depth case studies, the management tools used to manage coopetition at the inter-organizational level. Through multiples case studies in the same industry (the French grain merchants industry), we reveal the existence of differing management tools of the coopetition relationships. Some tools found by our research (tacit conventions, mediation arenas, coopetition inducers) seem particularly novel in the coopetition literature. The use of tacit convention and social pressure epitomize the embeddedness and the social construction of the coopetition relationship. It shows that inter-firm coordination can exist in a direct and informal way, without being locked into a rigid structure and without collusion. Moreover, we found that an external party can induce the coopetition and bring rival firms to consider a coopetitive relationship. This finding reveals that some tools can change inter-firms dynamics and rationalities giving rise to coopetition. Those findings lead us to reveal the perspective of a managerial engineering of coopetition and to suggest some embryonic basis to open the way for its development.