CPV code 79421100 designates Project-supervision services other than for construction work in the Common Procurement Vocabulary (CPV 2008), the EU classification used to describe the subject of public contracts.
79421100 is a leaf code — the most specific level of its branch — so it can be used directly as the main CPV code of a contract notice. If it does not quite fit, check the neighbouring codes under 79421000 (Project-management services other than for construction work).