The Metre Convention, also known as the Treaty of the Metre, is an international treaty that was signed in Paris on 20 May 1875 by representatives of 17 nations: Argentina, Austria-Hungary, Belgium, Brazil, Denmark, France, Germany, Italy, Peru, Portugal, Russia, Spain, Sweden and Norway, Switzerland, Ottoman Empire, United States of America, and Venezuela.
Woodcut dated 1800 illustrating the new decimal units which became the legal norm across all France on 4 November 1800
Historical international prototype of the metre, made of an alloy of platinum and iridium, that was the standard from 1889 to 1960.
The Pavillon de Breteuil in Saint-Cloud, Paris
International Bureau of Weights and Measures
The International Bureau of Weights and Measures is an intergovernmental organisation, through which its 59 member-states act on measurement standards in areas including chemistry, ionising radiation, physical metrology, as well as the International System of Units (SI) and Coordinated Universal Time (UTC). It is based in Saint-Cloud, near Paris, France. The organisation has been referred to as IBWM in older literature.
Pavillon de Breteuil in Saint-Cloud, France