The core activity of FiSYSTEMS encompasses three main areas: 1. **Technical Projects**: FiSYSTEMS implements projects in the fields of energy and IT. 2. **Personnel Consulting and Placement**: The company offers services in the field of personnel consulting and placement, including the placement of skilled workers and the implementation of competence assessments. 3. **Construction Projects**: FiSYSTEMS is also active in the construction industry, particularly in partnership with EGimmobilier. Overall, the core activity of FiSYSTEMS can be described as a combination of technical services, personnel consulting, and construction activities.