Les Carmes

Place de la Trinité

Fountain square where the Roman cardo runs beneath the lanes.

You're standing in Place de la Trinité, a small triangle of a square in the quarter locals often call the oldest in Toulouse. In the middle, three bronze figures rise from the basin of the fountain, the city's first monumental fountain, built in the 1820s. Now look at the lanes. The one running north is rue Saint-Rome and the one running south is rue des Filatiers.

Together they sit on top of the Roman cardo maximus, the main north-south street of Tolosa. In 2003, workers digging the metro found the road itself, along with a Roman sewer more than two metres tall that stayed in use until the Middle Ages, and the remains of a nymphaeum, a monumental fountain that was the first of its kind ever uncovered in Toulouse. Then step onto rue des Filatiers. Number 28 roasts coffee, number 30 sells madeleines, and across the way, number 27 is a bistro.

Two thousand years of buying and selling run under this one street.

Marché des Carmes

A morning food market trading here since 1892.

Under your feet now is one of Toulouse's longest-running food trades. The Marché des Carmes has sold here on place des Carmes since 1892, but don't look for the iron hall from those days. That structure was demolished in the 1960s, and the market now works from a concrete rotunda tucked beneath a car park, with daylight falling through its open sides onto the stalls. Step in and you'll find the morning crowd doing their shopping the way this quarter always has: fishmongers, cheesemongers, greengrocers, and bakers setting out produce that came in before dawn.

Take a loop past the stalls and notice who is arguing over the price of a fish. It opens Tuesday to Sunday from seven in the morning until half past one and closes on Mondays, and like every food market in this part of town, it shuts by early afternoon. If the stalls are already packing away, you've arrived after the real show.

Musée des arts précieux Paul-Dupuy

A five-euro museum of clocks and a Jesuit apothecary.

Around the corner, in an old townhouse at 13 rue de la Pleau, the Musée des arts précieux Paul-Dupuy holds the quarter's finer crafts. It costs five euros and opens Friday to Tuesday from ten in the morning to six in the evening, It closes on Wednesdays, and Thursdays are kept for booked groups. Inside, one whole floor is given over to clocks, hundreds of them, ticking and waiting for the hour. On the same visit you can study a carved bench from around 1500 and, best of all, the reconstructed apothecary of the city's Jesuit college from 1632.

Wooden drawers, ceramic drug jars, and brass scales line its walls, a complete seventeenth-century pharmacy reassembled indoors. It is a reminder that this district once made and sold precise things: instruments to measure time, and remedies to keep the body in time with it. Before you leave, note the building itself, a hôtel particulier of warm Toulouse brick that Paul Dupuy filled with his collection and gave to the city.