As a foreign student and tourist in Paris, I've noticed how impressive its roofs are. From these major monuments, we can see a magnificent panorama of Paris. For some years, the roofs have been used for other purposes: growing vegetables, restaurants, activities. My project will be dedicated to these initiatives that offer a new social model. Like a guide, this dissertation presents a few representative examples of ways to use the roofs of Paris, briefly analysing their construction, decoration and usages.