Madagascar is very often presented under the contradiction of being one of the most biodiverse country, but also one of the poorest economies of the world. A contradiction which is also the base of the dominant discourse of the environment and development aid, based on the paradigm of the ecological modernisation (Hajer, 1996) or modernisation (Robbins, 2004). This paradigm allows to link environment and economy instead of opposing them. Contrasting with a radical ecological approach which would need deep social and institutional changes, ecological modernisation is a more nuanced political discourse which does not put into question capitalism, but integrate environmental questions like pollution into the economic market. The economic development is said to be a condition of the sustainable protection of the environment, thanks to fiscal rules and introduction of proper technologies. Conversely, taking account of the environment would benefit to economy. The mining industry draws upon this paradigm and the contradiction of biodiversity wealth and economical poverty. For instance in Madagascar, mining are a very interesting proposal for the economic development of the country. The two biggest mining industries, Rio Tinto and Sherrit, which represents a direct forest investment of 5 billion US$ representing 65% of 2008 PIB. It should provide 18% of tax revenues by 2010 (Pelon, 2010). Yet, it also represents an important risk regarding social and environmental issue, with potential irreversible impacts. Conforming to international rules, the two mining industries of Madagascar are developing offset programs, to compensate the negative impacts by protecting forests in another threatened place. How are biodiversity offsets schemes developed? What is the governance of these projects? What are the controversies around these projects? Sociological methodology (interviews, analysis of literature and observation) will be used to describe those two case studies. This presentat