Assystem S.A. provides engineering and infrastructure project management services in France, the United Kingdom, and internationally. The company offers siting, licensing, environmental services, system engineering and design, construction management and commissioning, and nuclear safety and risk, as well as project management office, project controls, project management consultancy consulting, and other consulting services. It also provides digital transformation consulting, engineering information systems, data as a source of value, digital twin, 3D immersive technologies and tools, industrial control systems and cybersecurity, and security and site protection systems. It serves nuclear, hydrogen, renewables, grids, transportation, cities and territorial development, and defense sectors. In addition, the company offers decommissioning and waste processing, treatment, and storage services. The company was formerly known as AssystemBrime S.A. and changed its name to Assystem S.A. in June 2005. Assystem S.A. was founded in 1966 and is based in Courbevoie, France. Assystem S.A. is a subsidiary of HDL Development.