Paris Excavates Its Origins Under Notre-Dame

Notre Dame, Paris

Notre-Dame Square Excavation Uncovers 2,000 Years of Paris History

In early 2026, archaeologists opened a deep trench on the parvis (forecourt) of Notre-Dame de Paris, revealing continuous occupation ranging from medieval houses to a Roman-era neighbourhood. The dig – dubbed “the dig of the century”- was triggered by plans to rebuild and green the square (including planting 160 trees by 2028) following the 2019 fire. Under careful stratigraphic excavation, each layer has yielded artefacts spanning centuries: at just 2–3 meters depth, team members have found walls and cellars of medieval dwellings, while deeper down lie Merovingian and Carolingian-period grain pits and a densely built Roman quarter.

Archaeologists have opened an open-air trench on Notre-Dame’s plaza to examine soil layers dating from medieval times to Roman Lutetia (the ancient city on the Île de la Cité). The UNESCO-listed cathedral above was restored and reopened in late 2024, but engineers cannot plant new trees or install cooling features until the ground has been surveyed. By June 2026, the team had already removed old paving and dug about 4 meters (13 feet) deep. They report that “as soon as the concrete slab was removed” in January 2026, medieval walls and cobbled streets appeared. The layers identified so far include 12th–15th century house foundations just below the surface, Merovingian/Carolingian refuse pits from the 6th–10th centuries beneath that, and finally Roman-era structures dating to the 4th–5th centuries (ancient Lutetia) about 4 meters down.

Artefacts Reveal Everyday Life

The excavation has unearthed hundreds of objects that illuminate daily life in historical Paris. From the medieval layers came intact household vessels, jugs, cups and even a candlestick, plucked from old latrine pits where organic sludge had protected them for centuries. Conservator Lucie Altenburg notes that these finds are “not treasures like gold bars… but each element has great scientific value” for reconstructing past lifestyles. Intriguingly, many pottery fragments bear faint red inscriptions on their interiors. These mysterious medieval symbols (seen above) have so far defied interpretation and are described by archaeologists as “astonishing”. In the Roman layer, a corroded silver coin bearing the image of Emperor Constantine (reigned early 300s AD) turned up, instantly dating its context.

Many artefacts emerged from what were once cesspits. Among them are ceramic shards inscribed with undeciphered red markings. Hundreds of such objects have been carted off to the Paris Archaeology Centre for conservation and study. The conservators use X-rays, carbon-14 dating, 3D scanning and other analyses to reconstruct fragile pieces. Each find is logged, labelled, and photographed in situ during excavation, then packaged and transported to the lab at Rue du Pré. There is a team of anthropologists, zooarchaeologists, and others who clean and piece the fragments back together, building a catalogue of the parvis’s “lost city”.

Modern Work on Ancient Ground

The Notre-Dame dig is a preventive excavation mandated by French heritage law. Before major construction in historic zones, authorities (the DRAC Île-de-France) require full archaeological surveys. In this case, the city prescribed a 30×4 meter dig to create tree pits and access shafts, under the direction of lead archaeologist Camille Colonna. As work began in early 2026, Paris archaeologist Hugo Cador noted that on the Île de la Cité, “occupation is continuous since antiquity,” so he expected to encounter buried houses and trash middens. His team indeed methodically documented each stratigraphic layer: “Every change in the mortar, every shift in soil texture becomes a numbered ‘unit’” for study. New tools assist the effort: laser tachymeters record precise topographic points, and 3D photogrammetry maps the pit for later analysis.

Unlike rescue digs that rip through time layers only when threatened by construction, this excavation doubles as a research opportunity. The forecourt pit is dubbed by some reporters a “living museum”, where visitors waiting in line can peer over barriers at the “city under your feet”. School groups and tourists have watched archaeologists uncover animal bones, iron nails, fabric fragments and even one piece of a 2,000‑year-old vase handle. The project also feeds into Paris’s climate adaptation plan: in summer 2026, the team hopes to finish the dig and backfill in time for the square’s landscaping. Once the archaeological findings are recorded, the new plaza will feature 160 trees and gentle misting fountains to cool the area.

Historical Significance

This excavation is rewriting parts of Paris’s biography. By revealing the layer cake of urban history, from Roman Lutetia to Carolingian fields to a medieval suburb, it underscores how Notre-Dame stands atop a palimpsest of past cities. In essence, every inch of soil tells of centuries of human use and reuse. As archaeology student Yasmine Benali commented, seeing the layers makes the city “feel less like a postcard and more like something still being discovered”. Scholars are particularly excited by rare finds: Valentine Breloux, a conservator on the site, called the intact ceramics from latrine pits “miraculous”, and notes the Latin inscriptions hint at unknown medieval practices. Geologically deep, the trench also holds hope for even earlier history: experts hope to push below the Roman strata in search of traces of the Celtic Parisii tribe that founded the island centuries BCE.

For Paris’s citizens and visitors, the excavation has become a poignant reminder that Notre-Dame’s story extends far beyond its celebrated towers and spire. Every artefact removed is a tangible fragment of lives long gone: the horseshoes, shards and coins from these digs enrich our understanding of daily life in “every age” on the Seine island. As archaeologist Lucie Altenburg puts it, this chance to study a continuous 2,000-year record is “rare” and will “make a difference to the history of Paris.”