The structure and evolution of the sea breeze in southern France on 25 June 2001 is investigated experimentally and numerically. This study shows how interactions between the sea breeze, the synoptic flow and the complex terrain affect the sea-breeze structure, and quantifies and discusses the air-mass transport associated with the sea-breeze circulation. The analysis of the front propagation and the associated turbulent kinetic energy budget allows four distinct stages of sea-breeze front evolution to be identified. Quantification of the horizontal and vertical air-mass fluxes is related to these four stages: the horizontal advection is directly linked to the intensity of the sea-breeze flow. Two main mechanisms contribute to the vertical export within the free troposphere: anabatic upslope winds which are intensified by the sea-breeze flow and frontogenesis at the sea-breeze front which generates turbulence and mixing and upward motion