In this contribution, we propose to see steered communities of practice as a support to contextual ambidexterity. We show that the way such structures support both exploration and exploitation satisfies contextual ambidexterity hypothesis. We develop this proposition through the study of GDF SUEZ network of communities of practice. This study refines our understanding of the main aspects of contextual ambidexterity : a context favoring simultaneously performance and knowledge sharing, the balance between exploration and exploitation made at the individual level, and the ability to combine alignment and flexibility throughout an organization.