Kytom manages fitting out on occupied sites through a breakdown into zones of 80 to 150 m², delivered in cycles of 2 to 3 weeks. Each zone is isolated by temporary acoustic partitions (attenuation measured at 38 dB), with dedicated circulation and acoustically intrusive works postponed until after 6 p.m. Our 11 agencies mobilise a dedicated site manager for each project, responsible for the prevention plan compliant with R4214 and for weekly reporting to the real estate department. The method, deployed on more than 200 occupied sites since 2006, secures an overall timeframe of 12 weeks for 850 m² on average, without relocation, with an incident rate below 2%. Each phase is jointly validated with the works management director, HR and the works council.