As the dissemination of knowledge and scientific influence are structuring values of the université Paris Nanterre, the institution wished to adopt an open science policy in 2021, the year of publication of the French second National Plan for Open Science. The challenge for the university is to develop a political vision on this subject that is specific to its context, and to determine a strategy that is collectively supported by the departments concerned. On the organisational, networking and partnerships aspects: this paper will display how the université Paris Nanterre has been developing strong transversality between decision-makers, research department and library services in order to multiply and structure collaborations, and then included them in its organisation in a sustainable manner. This paper will underline how the development of its open science strategy has also strengthened the collaboration between the institution and other actors in the region or among the institution's partners in the open science and FAIR research data fields, but also helped opening up concerted partnerships with external actors in complementary fields such as open educational resources and OpenData. On the human resources and interservice collaborative aspects: this paper will showcase how designing an ambitious strategy and implementing coherent and collaborative services related to open science in a sustainable perspective of internal and external collaborations led the université Paris Nanterre to break down traditional frameworks of professional silos, and rethink traditional missions according to a bold and prospective vision. See the webinar full video on https://vimeo.com/748884203