The Marcel Sembat high school in Sotteville-lès-Rouen has the particularity to be crossed by a street and so is separated in two parts reconnected by a bridge building. A public park is located straight on the south side of the site. The entire school is divided in six buildings of different periods, from 30's to 90's. The project is a rehabilitation and an extension of the high school. We are presenting here the biggest part of this project, the one that gives his visual identity: the new workshops building. This part of the Marcel Sembat high school is dedicated to technical teaching about motors and vehicles mechanic. It demands big spaces with high heights and important surfaces. We opted for simple and easy understandable project, include workshops at the park with smooth lines which are connected to the park floor with their declivity. We proposed the demolition of two buildings, the reorganization of the workshops and the teaching spaces of industrial technology. We gather in a building unit all functions related to the workshops. The building starts at the boundary of the park and fits naturally to the site by the wavy design of its vegetated roof to varying curves and low height. The slight oscillations reveal the fringes of a park in motion in the trees shades. The main ideas of our proposal are, to find a unity and identity of the school in the whole site, to integrate and connect the high school and the park with the particular shape of the “blades”. We also wanted to create a public space around the crossing street by making a great plaza in front of the new workshops building. And finally our purpose was restoring the views and transparency to the outdoors, and perspectives on public space and landscapes. For that we used glass and translucent polycarbonate on the frontages. We also created some little patios between the “blades” to make skylights.The unity between the two sites around the crossing street is ensured by the creation of a new public space which will be surrounded by a new library oh the east side. This future "plaza" will be in the same time a meeting space, a walking or restoring area and the main access way to the high school. The new workshops are completed since this year and students and professors are taking possession of their new spaces. The site will be fully used from the next school year beginning in September.