This communication presents the first ideas relevant to the possibility of coupling together, thanks to constraints modelling, product configuration tools with process planning tools in an interactive and simultaneous way, in order to pass decisions made from one to the other. The first section introduces the problem and the general ideas of the proposed solution. Two constraints based models, relevant to product configuration and process planning, are presented. Then first investigations for coupling these two models and associated problems are discussed. An example illustrates our proposal throughout the paper.