The central Sahara has one of the most extreme climates on Earth. During the northern summer months, a large low pressure system caused by intense solar heating develops over a huge, largely uninhabited expanse of northern Mali, southern Algeria and eastern Mauritania. This Saharan heat low plays a pivotal role in the West African Monsoon. Moreover, the Saharan heat low region is dynamically coupled with the Mediterranean basin and the Sahel, two regions for which the predicted uncertainties associated with the impact of global forcing are quite significant. This large zone is also where the thickest layer of dust anywhere in the Earth’s atmosphere is found. The direct and indirect effects associated with desert dust are still poorly quantified, and the biases and errors affecting the radiative budgets in models over the Sahara are very important. It is known that such errors in modelled dust radiatif effects lead to errors in key dynamical features beyond the Sahara, with consequences for tropical development in the Atlantic and the circulation over the Mediterranean basin. The failure of climate models or numerical prediction models to capture main features of the Saharan weather is related to (i) the paucity of available data in this region, (ii) the difficulty to retrieve reliable space-borne “aerosol” products over deserts, and (iii) a lack of knowledge regarding the dynamics, thermodynamics and radiative processes in the Saharan atmosphere. To date, there exist very sparse data sources in this region that can be used reliably to enhance knowledge in terms of mesoscale processes or model validation. Large uncertainties remain regarding the position of dust sources, the quantity and the properties of mineral dust emitted the albedo variability at the mesoscale and the impact of aerosol radiative forcing on the atmospheric dynamics in the region. Such uncertainties can only be thoroughly evaluated, and hopefully reduced, in the framework of an ambitious project aiming to make decisive progress in terms of dynamics, thermodynamics and on the structure and composition of the Saharan atmosphere, by means of observations over the Sahara. Based on this, the interested French, British and German communities have decided to propose the FENNEC project which aims at (i) characterizing the Saharan atmospheric boundary layer, (ii) evaluating its representation in regional and global models, and (iii) improving “aerosol” products issued from space-borne observations. A key element of this programme is the organization of an international field campaign in the Saharan heat low region, which will include both ground-based and airborne detachments. On important aspect of this proposal, which aims at enhancing the knowledge of processes controlling the Saharan climate system, is to provide a framework for the French groups eager to contribute to this type of research and to ask for the means for achieving the proposed goals. The FENNEC-France proposal is built on contributions from 11 laboratories. The project benefits from support at the international level, amongst which support from the WMO program “Sand and Dust Storms Warning Advisory Assessment System” and the African Center of Meteorological Application for Development” (ACMAD).