The concept of intermediary intensive care units appeared in France with the progress of respiratory intensive care in the 1970s and an increment of the percentage of patients who were surviving an acute respiratory episode. It then became necessary to provide them with an optimal transition between the medical intensive care unit (ICU) and the home, thus explaining the emerging need for units of post-intensive care. At the present time, French health regulations recognize medical and surgical ICUs with a specific budget for equipment and nurses, and the specialized ICU which exists through a means share with the medical units (pulmonology, cardiology, etc.) inside which they are located. New regulations should make official the separation between medical and surgical intensive care units, intermediate (specialized) intensive care units and wards of reinforced follow-up, in a general perspective of improvement of the health network between the patient, home, and the different sectors of hospitalization (acute/chronic, public and private).