Saint-Eustache, Paris

Stand still for a moment at the edge of the square and listen. Behind you, the city moves underground, through the busy station of Les Halles. In front of you, a wall of pale grey stone rises in steep layers of buttresses, pinnacles and tall windows. Pigeons settle on the ledges. Somewhere inside, if you are lucky, an organ is practising, and the low notes reach you through the doors before you even see them.

This is Saint-Eustache, one of the largest churches in Paris. Many visitors walk past it on the way to the shopping centre and never look up. That is a pity, because this building tells one of the strangest stories in the city. It is a Gothic church with Renaissance clothes, a royal parish that grew up beside a market, and a place where great music and modern art share the same stone floor.

Construction began in 1532, under King Francis the First. The work took about a century to finish. By then, architectural fashion had changed completely. The builders kept the old Gothic plan, with its high vault, its tall columns and its ring of chapels. But they decorated it with the new language of the Renaissance, borrowed from Italy and from ancient Rome. So look closely at the columns and the arches. You will see pointed Gothic shapes carrying classical capitals and rounded ornament. Two centuries of taste stand side by side.

The church is named after Saint Eustace, a Roman general from early Christian legend. According to the old story, Eustace was out hunting when he saw a stag with a glowing cross between its antlers. He converted on the spot, and later died as a martyr. It is a tale, not documented history, but it was loved for centuries. Keep your eyes open as you walk around. The stag appears in the decoration more than once.

Now think about the neighbourhood. For hundreds of years, this was the site of the great food market of Paris. The writer Émile Zola called it the belly of Paris. Butchers, fishmongers, farmers and porters worked through the night just outside these walls. Saint-Eustache was their parish church. The smell of cabbage, fish and fresh bread would have drifted through the doors during Mass. This was a working church, not a quiet one.

It was also a church for the powerful. The royal palace of the Louvre stood close by, and many important families lived in this parish. The young Louis the Fourteenth made his first communion here. Cardinal Richelieu was baptised here, and so was Madame de Pompadour, the famous companion of Louis the Fifteenth. The playwright Molière was baptised in this church too. Inside, you can find the tomb of Jean-Baptiste Colbert, the powerful minister of Louis the Fourteenth. His marble figure kneels in prayer on top of the monument.

Here is a detail many visitors miss. Look at the main front of the church, the west facade. It does not match the rest of the building at all. It is calm, flat and classical, with columns stacked in neat rows. This front was added in the eighteenth century, when the original one had become unstable. And it was never fully finished. One of its two towers stops short. Stand back in the square and compare the two sides. The building is still waiting for a tower that never came.

Step inside, and the scale changes everything. The nave is very tall and fairly narrow, so your eyes go straight up to the vault. Light falls through the high windows and lands on the pale stone in soft bands. The air is cool. Your footsteps echo. Walk slowly along the side aisles, past the ring of chapels. Each one has its own paintings, its own glass and its own small history.

Saint-Eustache is famous above all for its music. Its great organ is one of the largest in France, with thousands of pipes. The present instrument dates from the late twentieth century, but it sits inside a much older carved case high above the entrance. In 1855, the composer Hector Berlioz presented his huge Te Deum here, with hundreds of singers and musicians. Franz Liszt also had work performed in this church. Regular organ recitals still fill the building with sound, and the low notes can feel almost physical.

The Revolution brought a very different mood. In the 1790s, the Catholic Church lost its power in France, and many churches were closed or given new uses. Saint-Eustache became a so-called Temple of Agriculture, a fitting choice for a building beside the city's food market. Later, worship returned. During the nineteenth century, the church also suffered damage from a fire and needed repair. The stone you see today carries traces of all these years.

Now for the second surprise. Search the side chapels and you will find art from our own time. One chapel holds a bronze altarpiece by the American artist Keith Haring, famous for his bold, simple figures. It was one of his last works. Another chapel holds a colourful sculpture by Raymond Mason. It shows the departure of the fruit and vegetable sellers when the old market left the centre of Paris. The faces are sad, crowded and full of feeling, like a farewell to a whole way of life.

That departure happened around 1969, when the market moved out to the suburbs. The old iron market halls were later demolished, and the area was rebuilt again and again. Outside, on the south side of the church, look for a giant stone head resting on its cheek, with a cupped hand beside it. It is a sculpture called L'Écoute, which means listening. Children climb on it, and tourists sit beside it for photos. It feels like the head is listening to the church.

As you leave, turn around once more. Look at the flying buttresses, those stone arms that hold up the high walls from outside. Look at the windows and the carved pinnacles, darkened by city air. Then look at the modern glass roof of Les Halles nearby, and the crowds coming up from the station. The market is gone, but the church is still here, between the old Paris and the new. Listen... perhaps the organ is still playing behind you.