The harmonised consumer price index (HCPI) is the indicator used to assess compliance with the convergence criterion on price stability in the European Union Treaty (Maastricht). For France, the national economic territory comprises Metropolitan France and the overseas departments. The index is designed expressly for international comparison purposes. The methods used by the European Union Member States to calculate their national price index are distinctly different. Bearing in mind the need to determine a threshold as important as inflation, they therefore cannot be used to adequately compare price rises in these countries. This is why the harmonised consumer price indices are calculated with methods and content that ensure better comparability. The main difference with the national consumer price index lies in the processing of social protection and education. In the HCPI, only the proportion borne by the consumer (after repayment) is taken into account.