Four years ago, a major fire broke out in Notre-Dame de Paris Cathedral. The French government has given the rebuild five years. To meet the key outcomes around schedule, health, and safety, the project has coordinated the daily presence of various types of workers specialized in restoration activities (archaeologists, carpenters, stone cutters, and so on). This class will focus on how Setec Opency (specializing in construction management) has digitized the execution planning process using 4D building information modeling (BIM) and digital technology, integrating the work sequencing and the opportunity of planning optimization, while minimizing the risk of accidents. Setec Opency will show how it has taken into account multiple constraints: tight deadlines, the configuration of a historical building (large volume, 4,800 square meters, great height), 120 subcontractors, and 400 workers over nine construction phases costing hundreds of millions of euros. See how bringing 4D to the field with VR/XR will help the renaissance of an 800-year-old legacy.