"The bureau for fiscal, economic and environmental policy (« bureau de la fiscalité et des instruments économiques pour l’environnement », part of the Environment ministry) produces quantitative economic studies of the impact of environmental policies (and of the environmental beahvior of the various economic actors) and evaluation tools. This bureau has namely developed a micro simulation tool to valuate ex ante the social impact of energy policies (evaluating the impact of the price increase for fossil fuels on various types of households). Throughout the past, the bureau has conducted econometric estimations on price elasticity for fuels. The bureau now wishes to update and extend the microsimulation model of household energy expenses (Prometheus model). This tool’s purpose is to enable the simulation of fiscal policies related to energy and inequalities in access to energy. Many schemes are based on eligibility criteria depending on legal or fiscal notions (income for fiscal reference per fiscal share, a notion which is linked to that of fiscal address). The national housing survey carried out in 2013 (ENL 2013) and the social and fiscal income data (POTE) will enable us to access data at the “fiscal household scale” and access (and thus take into account) the income of said household. The current version of the Prometheus model cannot go beyond the fiscal household and integrate fuel expenses. Yet energy policies, fiscal or addressing inequalities in access to energy are multidimensional and cover the housing and mobility aspects. Extending the Prometheus model to transport requires information on professional (and similar) mobility and fuel consumption this mobility generates. This information is available in the 2011 family budget survey (“enquête budget de famille –BDF 2011-“) database and the 2008 national transport survey (“enquête national transport et déplacement 2008”) at a detailed level which will enable to link fuel consumption expenses to the social characteristics of households and to where they live. The bureau also foresees producing estimations of price elasticity for residential energy consumed by households, so as to better approach inequalities in access to energy and compensatory mechanisms which could mitigate price increases. The technique foreseen (panel econometrics) will require working on many editions of the ENL and BDF surveys. "