What Roman amphitheatre in Paris is now a public park?

The Roman amphitheatre in Paris that is now a public park is the Arènes de Lutèce.

Built in the 1st century AD in ancient Lutetia, the arena could accommodate roughly 15,000 spectators. It combined theatrical seating and a performance space with an amphitheatre arena, where spectacles including gladiatorial combats could be staged. Its unusual layout had seating around more than half the arena, giving it features associated with both Greek theatres and Roman amphitheatres.

The remains were rediscovered in the 19th century during work connected with the Rue Monge and a proposed tramway depot. Writer Victor Hugo and other preservationists helped campaign against destroying the ancient structure. After restoration, the city opened the site as a public square in 1896.

Today the Arènes de Lutèce sits in Paris’s Latin Quarter and functions as a public green space. It is often confused with the Thermes de Cluny, another major Roman remain in Paris, but the Baths of Cluny were a bathing complex rather than an amphitheatre.