The multi-criteria decision aiding (MCDA) process can be applied in many fields of our life to make "better" decisions : health-safety, financial and banking systems, environment management, planning of urban infrastructures, space engineering, etc. This process involves many actors, among which the decision aider (or analyst) and the decision maker. The main purpose of this work is to formalize and model the MCDA process via model-driven engineering techniques, and to test it on a few use-cases. We motivate this work by showing why the MCDA researchers community could benefit from a meta-approach to decision aiding. Some of the questions which will be answered by this work are thus : How can the analyst be assisted in the choice of the MCDA method ? How can the expertise of analysts be modeled ? How can the dialogue between the decision maker and the analyst be guided ? This work thus tries to create a step-by-step guide of the aiding process, which will be useful for novice and for advanced researchers. This model is designed in UML which will help us in the future to create model-based support software and make connections with other applications.