International audienceThis chapter offers a detailed sociological perspective on the role of investment-oriented policy instruments (subsidies, fixed tariffs, tenders) in triggering and shaping the recent development of renewable energies in three countries (France, Germany and Tunisia). Bringing together recent developments in STS (concerned markets, capitalisation), it shows that, despite their economic framing, these instruments trigger processes which deal with multiple values. They also sustain the emergence of collectives concerned with their effects – called their ‘milieu’ - which they become co-dependent upon. Such processes lead to iterative adjustments and developments that carry with them their own politics. While they sustain the emergence of political ends beyond those directly foregrounded by these instruments, they also prove to be very unevenly equipped to address emergent concerns