Certification and ecolabelling are forms of private governance meant to reflect sustainable development issues. These instruments encourage 'good' environmental and social practices, many of which are akin to climate change mitigation and adaptation approaches. To make it clear how effective they can be in that role, we present them here, recalling that they are at once standards for best practices, by definition supposed to inform and guide stakeholders' choices, and market incentives (bonuses, minimum prices, etc.) to change production practices. Despite their advantages, voluntary sustainability standards are proving to be ambiguous tools for meeting the challenges of climate change. (Résumé d'auteur)