Industry influence over pesticide regulation has been central to the US anti-pesticide activism for decades. In France, unions and NGOs denouncing the harmful effects of those substances on the health and the environment rarely brought up this issue. Recently, it gained prominence as “Conflict of interest” (COI) became a central element of their protest repertoire. This article analyze this time difference. It describes three related dynamics – the institutionalization of risk assessment, the development of investigative environmental journalism, and the professionalization of environmental health advocacy organizations – that contributed to establishing the issue of industry influence as a central element of the protest repertoire of the US and, later, French activists engaged in the fight against pesticides. For them, COI is now a central concept that includes not only interpersonal financial relations between public agents and industries, but more broadly the corporate leverage on public expertise and decision.