The Parisii were a Gallic tribe that dwelt on the banks of the river Seine during the Iron Age and the Roman era. They lived on lands now occupied by the modern city of Paris, whose name is derived from the ethnonym.

Gaul was a region of Western Europe first clearly described by the Romans, encompassing present-day France, Belgium, Luxembourg, and parts of Switzerland, the Netherlands, Germany, and Northern Italy. It covered an area of 494,000 km2 (191,000 sq mi). According to Julius Caesar, who took control of the region on behalf of the Roman Republic, Gaul was divided into three parts: Gallia Celtica, Belgica, and Aquitania.