Discovery beneath the hospital

Archaeologists excavating the courtyard of the Hôtel-Dieu hospital on the Île de la Cité in central Paris have uncovered a 20-meter fortification wall dating from the late Iron Age. The preventive excavation, which began in February 2026 ahead of planned hospital restructuring work, reached a depth of four meters before exposing the stone and timber structure. Researchers initially expected to find remnants of medieval occupations, roads, or standard Roman-era habitation layers. Instead, teams from the Regional Archaeology Service (DRAC Île-de-France), the City of Paris, and the French Ministry of Culture uncovered the base of a defensive rampart standing approximately one meter high. The wall rests on a two-meter-thick artificial platform composed of packed sand and gravel. Excavators also recovered a Gallic spearhead directly at the foot of the wall, first-century BC amphora fragments, and the charred remnants of an adjoining wooden building.

“The architecture of the wall, with these large blocks and this system of crossed beams, very quickly made us think of a wall of Gallic tradition.”

Wall length20

Burial depth4

Platform thickness2

Wall height1

Wall length

20 m

Burial depth

4 m

Platform thickness

2 m

Wall height

1 m

Data from the article text

Dating and evidence of burning

Initial radiocarbon analyses conducted on the preserved wooden beams place the construction of the rampart between 200 BC and 10 BC. Both the timber framework and the adjacent soil layers contain distinct burn marks, pointing to a severe fire during the final decades of the first century BC. This physical layer corresponds closely with written accounts of the Roman conquest of Gaul. In his historical records, Julius Caesar wrote that the Gallic Parisii tribe intentionally burned their fortified settlement, known in Latin as Lutetia, and broke down their bridges in 52 BC to deny the stronghold to advancing Roman legions. Although researchers emphasize that scientific testing cannot yet pinpoint the burn layer exclusively to the year 52 BC, the combination of defensive architecture, weapon artifacts, and destruction by fire matches the recorded battle conditions.

“Scientific prudence still requires verifying its function and chronology, but the convergence of indices is now particularly remarkable.”

Resolving the debate over ancient Paris

The discovery offers physical data to address a centuries-old question regarding the precise location of pre-Roman Paris. Julius Caesar described Lutetia as an oppidum, a fortified center of tribal power, situated on an island in a bend of the Seine River and connected by bridges. However, an absence of pre-Roman remains on the Île de la Cité had led scholars to debate the account. During the 1990s, extensive archaeological excavations in Nanterre, a suburb west of Paris, uncovered substantial late Iron Age settlements, prompting numerous historians to suggest that Gallic Lutetia was established there rather than in the modern city center.

Matthieu Poux, an archaeology professor at the University of Lyon II who previously supported the Nanterre hypothesis, confirmed that the wall provides conclusive evidence for the island location. Paris Deputy Mayor Emmanuel Grégoire inspected the four-meter trench and noted the significance of identifying the city's probable origin point. Archaeological operations directed by David Couturier will continue at the Hôtel-Dieu site for several months to document additional settlement layers before hospital construction proceeds.