Public spaces that the pedestrian is found to browse last fifteen years tend all to a minimal materiality expression. While destabilizing, these areas are to be strong proposals for new public space and urban experience of passersby. How do we lose or do we take foot in such situations? Through the observation of walking rhythms in urban public space, we question the body movement as an expression of the meeting of passersby and its environment, and their joint update to opening a new space. Thus we ask the question of ambiances as a movement, or in other words, the question of the ambiance, not "already there", but which exists by the movement of bodies. We will try to present some elements to reflect on how passers take part in ambiances in which they will move and be moved.