This paper investigates the emerging situation in which the development of software are involved both free and private components. With regard to the present empirical case, it is noteworthy that many problems of industrialization and exploitation are based on the hybridization of technology. The purpose of the paper is to understand how a partnership contract is an "object of mediation" in collaboration. The concept of "objects of mediation" shows that a same artifact plays many roles in a sociotechnical network. According to the Actor Network Theory framework, this analysis is based on the empirical case: the Pupitre Virtuel. In fact, over twenty months' participant observations and interviews have been done to identify the main elements of the controversies between different actors. The results show that the specificity of technology carries many controversies around the development of software and contribute to explain the failure of this collaboration. Between controversies and compromises, the partnership contract has different natures and plays different roles of mediator.