The Breteuil pavilion is located in the commune of Saint-Cloud, in the Hauts-de-Seine department, a few kilometers west of Paris.
This is a former trianon (that is to say an annex pavilion of a castle of the royal domain, under the Ancien Régime) which depended on the castle of Saint-Cloud. The latter was burned during the war of 1870, and only the vast park of 470 hectares and a few annexes, such as the Breteuil pavilion, remain.
This was built in the 17th century according to the plans of the architect Thomas Gobert on behalf of the king's brother, the Duke of Orléans, and was inaugurated by Louis XIV in 1672. It served as a party pavilion at from 1680.
Overlooking a terrace itself overlooking a fountain of Venus, it was remodeled in 1743 for the marriage of the Duke of Chartres (son of the Duke of Orléans). The building was then the residence of the Abbot of Breteuil and then of his nephew, the Baron of Breteuil, who had negotiated the purchase by the king of the domain, and who as a thank you was able to settle there. He also left him no name.
Restored under Napoleon I, damaged in 1814, the pavilion was made available in 1848 to the Ministry of Public Works which rented it as a "pleasure dwelling with gardens and outbuildings".
Under the Third Republic, renovated, the pavilion houses the International Bureau of Weights and Measures (BIPM). As a result, it is governed by an International Committee responsible for carrying out for the adhering states all the planned determinations, relating to measurements of length and mass, up to temperatures and electrical units. The mission of the BPIM is to ensure global uniformity of measurements and their traceability to the International System of Units (SI). He carries out research related to metrology. It organizes or participates in international comparisons of national measurement standards and carries out calibrations for Member States.
Architecturally, the building is in the neoclassical style.
Guided tours of the pavilion are offered during Heritage Days by BIPM agents, with discovery of the interiors, exteriors, and a unique collection of old instruments. Information on +33 1 45 07 70 70.
The rest of the year, the exterior of the pavilion can be observed during a walk within the park which has become the National Domain of Saint-Cloud (on its south-eastern part). Free admission. Information on +33 1 41 12 02 90.
