The objective of the CO3D (3D Optical Constellation) mission is the fully automated production of a worldwide accurate Digital Surface Model (DSM). This DSM is generated from stereoscopic acquisitions made by a new generation of high-resolution optical satellites, also called CO3D. The DSM's accuracy is one meter in relative altitude for moderate slopes and four meters in absolute altitude, with a grid spacing of one meter. Each of the constellation's four satellites provides images with a resolution of 0.50 m in the red, green, blue, and near-infrared bands. Satellite resources are shared between, on the one hand, CNES (National Centre for Space Studies), which serves French institutions (government, scientists involved in global Earth observation) and benefits from dedicated access and preferential pricing, and on the other hand, ADS (Airbus Defence and Space), customers interested in 2D and 3D products. This program is organized through a public-private partnership between these two entities. The constellation was launched on July 25, 2025. This article presents the mission's main challenges, the program's organization and timeline, as well as the system's implementation, including the space and ground segments and their key innovations. Finally, the initial results obtained during the commissioning phase are presented, highlighting the range of applications targeted by the mission.