There’s an aroma from another stall in this part of the market, more elemental even than the mushrooms. It’s white potatoes: they have a distinctive flavour from the limestone in the soil and all the seaweed fertiliser. They’re harvested just before maturity, and their cooked skins feel like silk coming away in the mouth. Something as simple as a potato becomes magic in the Charente-Maritime region. It’s the same with its salt, the “white gold” harvested and traded here since the 11th century. Incredibly delicate, almost sweet, with faint traces of magnesium and calcium, it made La Rochelle, by the 17th century, fiscally and politically supremely important to France. Salt pans fill the mesmerising island marshes. On Oléron it’s possible to take the six-mile loop around them on a bicycle, but riders should pedal with care: during high season on either island, bell-chiming shoals of cyclists pass, sometimes on tandems, sometimes snogging, or shouting about directions under circling gulls.

Baked goods at La Flotte market
Oliver Pilcher
Antiques gallery in Saint-Martin-de-R
Oliver Pilcher
On Ré one quiet day in late summer, I cycle from Ars-en-Ré through the marshes towards the island’s smallest village, Loix, my route fringed in salicornia, a marsh samphire, turning Septemberishly rusty. Images and memories become weirdly indistinct in these marshes, but on this day I’m sure I can recall a sundial roughly painted on the side of a salt worker’s hut. White horses pushing their muzzles into spiky marram grass. And somewhere near La Couarde-sur-Mer, paludier Hugo, his hands tanned and streaked after a summer hard at it, taking a break from his work to show me the coarser salt at the bottom of his pans, metallic grey and briny, perfect for preserving. And then the Fleur de Sel: the white salt harvested from the surface in a thin film, light as sea spray when dried, amplifying any flavour.

Seafood at La Cabane de la Patache on the island
Oliver Pilcher