Several high schools in the south east of France are subject to a major work of renovation. These works need to take into account the problem of summer comfort for a better well-being and intellectual performance of students. One of it was chosen to carry a study on the specific constraints for achieving summer comfort. The study consists of surveys, monitoring and simulations. This enables to determine the major causes of the summer discomfort in field and to propose several passive solutions. These solutions were assessed by simulation using a dynamic simulation tool. Thermal standards and regulations were used to evaluate the resulting ambiances. In the paper, the requirements relative to summer comfort and the constraints encountered during the preparation for the rehabilitation of the studied high school will be presented. Results of parametric and simulation studies will be given. It concerns the envelope and the ventilation system focusing on a study of nocturnal ventilation using different possible strategies. And finally, recommendations about summer comfort will be given for future rehabilitation in educational buildings.