Pavillon de Breteuil is a building located in Sèvres, France near Paris. It was inaugurated by Louis XIV in 1672. It is in the park of the former royal Château de Saint-Cloud, which was destroyed in 1870.
The building had been used since 1875 by the International Bureau of Weights and Measures. Following an agreement signed on 25 April 1969 between the International Committee for Weights and Measures (French: Comité international des poids et mesures) (CIPM) and the French government, the Pavillon de Breteuil enjoys extraterritorial rights similar to those enjoyed by embassies.