Archaeologists excavating beneath the streets of Paris have uncovered a series of remarkable artefacts offering fresh insight into the city’s prehistoric, Roman and medieval past.
The discoveries, unveiled ahead of the European Archaeology Days taking place from 12 to 14 June, were uncovered during preventative excavations carried out by the City of Paris Archaeology Department in recent months. Together, the finds offer a rare glimpse into the many layers of history lying buried beneath the modern capital.
Among the most unusual discoveries was a polished stone axe dating to the late prehistoric period unearthed during excavations at 16 Rue Cujas in the city’s 5th arrondissement in the autumn of 2025. Archaeologists were surprised to find it buried among ancient Gallo-Roman remains, so they speculated that it may have been kept as a symbolic rather than practical object.
Researchers think the axe might have been considered a “thunderstone”— an object that Romans believed would have fallen from the sky when Jupiter’s lightning struck the earth. Such things were believed to have supernatural powers and were often used as charms or buried near homes and religious places as protection from harm or protection from fire and worship.
Elsewhere in central Paris, excavations in the courtyard of the Conciergerie uncovered a medieval horseshoe alongside an ornate harness fitting dating to the Middle Ages. Beyond their archaeological significance, the objects offer insight into the important role horses played in medieval society, particularly within royal culture, where they were central to transport, hunting, ceremonial processions and displays of prestige and power.
Another discovery was made not in the streets but in the waters of the Seine River. Paris river police recovered a mysterious metallic sphere in June 2025, which initially raised fears that it was an unexploded war weapon.
After specialists ruled out any danger, archaeological experts discovered that it was a 19th-century coffee roaster that roasted green coffee beans. The unusual discovery is a reminder of the forgotten objects buried in the riverbed of the Seine that are still with us today (and still found in the maintenance and recovery work).
At the Curie Institute, excavations revealed the remains of a 1st-century AD building illustrating the mingling of Gallic and Roman traditions in the decades following Caesar’s conquest of Gaul.
While the walls of the building were made of raw earth in the traditional way of Gallic architecture, there were also distinctly Roman elements: concrete floor, masonry drainage gutter and stone staircase. Archaeologists are still assessing the site to gauge whether the building was a residence or workshop or a commercial space.
Other discoveries were made during excavations at the Palais de la Cité where archaeologists discovered hundreds of medieval terracotta paving tiles dating back to the 14th century. The glazed tiles with geometric patterns, flowers, animals and heraldic symbols that once adorned one of the most important royal centres in medieval France were among them.
Archaeologists say the discoveries highlight the extraordinary depth of history still buried beneath modern Paris, where centuries of human activity have left behind countless traces that continue to await discovery.
Header Image Credit : Ludivine Boizard
Sources : Paris
