The aim of the work covered by this article is the quantification of the effect of paleoclimates on heat transfer in the Paris Basin. Based on temperature measurements over as many as 20 formations and traversing 2700 m of rock, we describe decrease in the apparent conductive heat flux over the first 1500 m and indicate a systematic decrease in this flux at the aquifer formations throughout the sediment pile. After a critique of the use of a profile based on average flux per geological formation, we choose a temperature measurement reference. 1D simulation of different paleoclimate scenarios shows that these can explain half of the observed decrease in heat flux in the upper levels. Several hypotheses are then proposed to explain the contributions of other phenomena to the variations observed in the apparent conductive flux. (C) 2016 Elsevier Ltd. All rights reserved.