The project is built in an area surrounded by public facilities in a residential suburban character near Paris. The proposed extension is built while maintaining the wooded character of the bottom plot. The neighboring houses are built in traditional forms with gabled roofs, thereby extending the crib comes with a gabled roof curved. To insert the building in an environmentally sound approach, structure, roofing and siding are made entirely of wood components. Although the structure is wood, the generally rounded shape of the building is "born" of the desire to represent "...a boa constrictor digesting an elephant ..." This analogy refers to the stories of the famous story "The Little Prince" by paying tribute to Antoine de Saint-Exupery ... when he was a little boy.The administrative departments of the city wanted to enlarge the capacity of this structure by extending the building housing an additional section of the 30 children. This new part of building extension is composed of three spaces (an space activities and two sleeping spaces. The entire surface of the extension is 193 m². These three areas are unified by a single vegetated roof cover forming a whole and combining the three components of the program, however well differentiated. Although the roof slope is performed with a plant complex to enhance the performance and thermal comfort in both winter and summer thermal inertia. As for the facade, the path is clear siding installed vertically due to the weaker form.To meet the demand to achieve a sustainable building with a reasonable energy consumption and in a very short period of construction (three months on the extension of wood), the structure of the building was made entirely of plant and wood frame walls including insulation and protection complex rain and steam were assembled at the factory and assembled in three days. Douglas siding requires no maintenance and installation is a clear path following simple mathematical system at the end gives the impression of a random poses, two widths 40mm and 120mm are used in a series 1-1 (short and a wide ...), 2-2 and 3-3. This method of installation has been specially designed for this building with an educational objective to develop the awareness of children. The windows are anodized aluminium frames with very natural tone varies according to the internal use of the building, ranging from very small windows in relation to the use of space by children and very large windows in relation to existing trees with high stem in the garden.Skydomes of circular roof are planned to provide natural light inside the building to minimize the maximum use of lighting. Access to the garden plot at the bottom is protected by a canopy using playground so that children can be protected from the weather. The underside of the canopy is left showing the apparent structure coverage and high-performance compact heat. This coverage is achieved with very large solid wood panels laminated type in BSS of the firm "Binderholz”. Functionality, rationality and play areas are aligned with the processing of the coronation of the building; it represents a boost in the dynamism of the awakening of the children