Wassy is a commune in the Haute-Marne department in north-eastern France. Its population, as of 2019, is 2,819. Wassy has been twinne…Wassy is a commune in the Haute-Marne department in north-eastern France. Its population, as of 2019, is 2,819. Wassy has been twinned with the German town of Eppingen in north-west Baden-Württemberg since 1967.