CPV code 79623000 designates Supply services of commercial or industrial workers in the Common Procurement Vocabulary (CPV 2008), the EU classification used to describe the subject of public contracts.
79623000 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 79620000 (Supply services of personnel including temporary staff).