The maturation level of organic matter, in Oligocene and Miocene sediments from the Swiss and French Molasse basin, reveals a close relationship between very low temperature metamorphism in the foreland basin and the tectonic history of the Alps. Measured mean random vitrinite reflectance of outcrop samples range from 0.21 to 0.97%. Generally, the degree of thermal maturity increases towards the Alps, probably due to increasing burial in the same direction. Second order variation of the coalification pattern in the Plateau Molasse may be related to a regional discharge of warm fluids controlled by tectonic structures. Clay mineral analysis and fluid inclusion studies support the coalification results.