This research aims to shed light on the facilitating role of non-commercial, open-access fablabs in commercial entrepreneurship, particularly for innovations emanating from less conventional entrepreneurial figures: users. In this perspective, qualitative interviews were conducted with users-innovators/users-entrepreneurs on the one hand, and fab managers on the other. Using a process-based analysis approach (“from maker to market”), three key contributions are proposed: (1) fablabs are facilitators of user entrepreneurship but the resulting “treatment effect” is limited, and sometimes even counterproductive; (2) commercially oriented entrepreneurship is contrary to the culture of fablabs, inducing an ambivalent “treatment effect”; (3) fablabs’ action capabilities tend to transform towards “accidental” pre-incubation. These results enrich two theoretical fields: user entrepreneurship and entrepreneurship in fablabs and provide new elements to support user entrepreneurship and to better identify the postures and capacities for action of fablabs in this field.