town, Yonne département, Burgundy région, central France, southeast of Paris. The Old Town, situated on the right (eastern) bank of the Yonne River, is surrounded by shady boulevards and promenades built on the site of the old Roman walls. The railway station and industrial zone are located on the left bank.

Before becoming a major Roman settlement, the town was the capital of the powerful Gallic Senones, from which the name Sens is derived. In medieval times it was an ecclesiastical centre with five abbeys. The council at which St. Bernard of Clairvaux condemned the doctrines of the philosopher and teacher Peter Abelard for the second time was held there in 1140. The 12th-century English martyr Thomas Becket resided (1166–70) at the Monastery of St. Colombe (largely rebuilt), located 1.2 miles (2 km) north of the city. The French king Louis IX was married in the cathedral in 1234. The ecclesiastical province of Sens was dismembered in 1627 when Paris became an archbishopric, but the archiepiscopal see was reestablished in 1821.

The town's chief monument is the cathedral of Saint-Étienne (mid-12th to early 16th century), which was one of the earliest important Gothic churches. Its 12th-century architect, the master mason William Of Sens, based the design of the choir of Canterbury cathedral in England on that of Saint-Étienne. The facade has three portals with fine 12th- to 14th-century sculptures. The south tower of the west facade is the only tower completed; it collapsed in 1268 and was reconstructed during the 14th–16th century. The cathedral has magnificent 12th- to 17th-century stained-glass windows, and its treasury contains a rich collection of ancient fabrics and vestments, including those of Thomas Becket. The 13th-century Officiality (restored by Eugène-Emmanuel Viollet-le-Duc in the 19th century), which now houses a museum containing important examples of Gallo-Roman sculpture, and the largely 16th-century Archbishop's Palace adjoin the cathedral.

Sens lies in a rich agricultural region, and industry has developed there only since the 1960s. The present-day town retains a highly diverse manufacturing sector, with many pharmaceutical, electronic, and food-processing companies. Many of Sens's industries and services have merged with those of Paris. Pop. (1999) 26,904; (2005 est.) 26,800.