Aix marks the spot for a free summer holiday

A fancy pad in the town where two great artists lived – this house swap turned up trumps, writes Sankha Guha

The eurozone is no steal for British families these days and, moreover, the south of France has never been a bargain holiday. So when I get a breathless call from my budget-strapped sister in Aix-en-Provence her glee takes me by surprise. "This is amazing!" she stammers in excitement. "The best yet. We have our own private hill, our own forest, eight bedrooms, swimming pool ..." She hasn't won the lottery exactly, but her home-exchange holiday this year has come up trumps; a terraced house in damp south-east London swapped for a rambling hilltop estate in Cézanne country. "Unbelievable," she gushes. "You just have to see it."

Four days later I am on the Eurostar to Avignon. Kent, the tunnel and then pretty much the whole of France whizz past in a six-hour blur. Compared with the experience of modern flying, with its cattle-truck indignities and security neuroses, the journey is a revelation. One caveat – the catering seems to have taken its cue from old BR standards rather than anything recognisably French. We are on time when we pull into Avignon Central shortly after 2pm. The air is warm and suffused with light, offering a full-blooded Mediterranean embrace after the squibby non-event of our summer.

The exchanged home exceeds even my raised expectations. The smell of pine resin – cool and seductive – greets us on arrival. The home is made up of a principal house plus an annexe that rambles up a forested hillside; also scattered around the estate there are a gatehouse, gardens, terraces, an abandoned tennis court and a hotel-sized swimming pool which overflows to an artificial waterfall. A forest trail leads up to the brow of the hill with commanding views of Mont Ste Victoire – the limestone ridge that will be for ever known as Cézanne's mountain.

"I shudder to think what they think of our hovel in London," says my bemused brother-in-law. Their family home near Greenwich is hardly a "hovel", but if the French family is expecting a pool or acres of grounds, it will be disappointed. The apparent asymmetry of the exchange is explained by the magnetic pull of London. "We've had diplomats from the Caribbean, wealthy couples in San Francisco wanting to swap," says my sis. "London is such a draw," interrupts her husband. "And it's so expensive to stay that even somewhere as ordinary as where we live is appealing."

Aix has its own draws, most relating to its favourite son – Paul Cézanne. He was born here and died here. And in between did much of his best-known work here. Metal medallions embossed with his name are sunk into the pavements of the old town, denoting a heritage trail dedicated to the artist. Sites on the trail include his school, his atelier, his father's bank (Cézanne did not have to serve time as a starving artist in a tiny garret) and Jas de Bouffan, the family mansion, which the painter decorated with murals. The house and grounds are open to the public, and for Cézanne fans they must trigger jolts of déjà vu. The pool he painted in the winter of 1873 is still there but everything around it is altered. The leafless sapling that divides the painting in half has been replaced by a towering confident tree, and the house on the hill behind (if it still exists) is obscured by multilayered foliage.

The interior has also changed. There are no original paintings even in the ground-floor salon where he once worked. The room has been converted into an audiovisual Cézanne Experience. In the darkened interior a portentous voice extols the genius of the painter to a backing track of dreamy music while three projectors cast pixellated images of the murals (long scattered to collections across the world) back on to their original positions. My favourite bit comes when the techies who devised the show have a go at improving Cézanne's depiction of water by adding a digital rippling effect to the projected image of one of his works.

The curators of the Picasso/Cézanne exhibition at the Musée Granet have restrained their own techies, letting the 114 paintings, sculptures, drawings and engravings on display weave their own magic. The exhibition is heavily skewed towards Picasso and does at times feel like a marketing exercise that seeks to claim the artist as a true Aixois.

His debt to Cézanne is well acknowledged but the blurb here labours too hard in positioning the "master of Aix" as a John the Baptist figure to Picasso's messiah. Picasso's affection for the area is, however, evident, especially in a series of paintings that reveal his happy domesticity when, aged nearly 80, he took up residence in the Chateau de Vauvenargues just down the road.

It is hard to imagine how anyone could feel anything but joyous here. The famous light of Provence bouncing off the pastel pink and honey walls of the old town banishes memories of cold and dark climes. On market day, the Place des Prêcheurs is a riot of colour, and heaves with crowds picking through stalls selling traditional fabrics with tiny repeating motifs of provençal flowers and insects, or equally vivid raffia bags that have travelled all the way from Madagascar.

The brightest colours though radiate from the fruit and veg stalls. Tomatoes, peaches, peppers, courgettes and gourds lie scattered in ready-made still-life compositions, almost too voluptuous to eat. Cafés spill on to the streets, as do the aromas of fresh espresso and patisserie, while waiters busy themselves dispensing chilled pink wine and juicy green olives. The cumulative sensations add incrementally to the pleasure of the moment – all summed up in that little French cliché, joie de vivre.

Back at the estate, my sister explains that the real bonus of the home exchange idea is not simply the free accommodation, but the privilege of plunging into someone else's life. And if you can read people by their chattels, the owners do seem thoroughly likeable. The house is crammed with eclectic collections of art and artefacts strewn around with a casual disregard for display. They are simply objects to be lived with.

A similar disregard applies to the fauna that colonises much of the house. Fascinating little millipedes, hordes of spiders and fearsome-looking creatures my niece calls "horrendipedes" have the run of the place. The femme de ménage appears twice a week but must be under strict instructions not to disturb the resident creepies. She comes, she goes; not a single web is molested and no millipede is given its marching orders.

This year (and this year only) visitors can get a similar privileged insight into the domestic set-up of the Picasso household while the artist occupied the Chateau de Vauvenargues on the north, less famous side of Mont Ste Victoire. Picasso was clearly tickled by the idea of buying up Cézanne country. He announced to his dealer that he had bought Ste Victoire. "Which one?" asked the dealer, imagining Picasso was referring to one of the many Cézanne paintings of the mountain. "The real one," boasted our man.

Visiting is no routine matter. The current owner, Catherine Huton, the painter's stepdaughter, is clearly irked by the stream of tourists who have insisted on banging on the gates. A rather testy notice outside announces "Accès Interdit" and that "Le Musée est a Paris". Translated into the vernacular it says Bugger OFF!

This year, though, Huton has agreed to open the chateau to the public for the first time as a complement to the Cézanne/Picasso exhibition. Visits are limited to guided parties of 19 people at a time; cars must be left in a designated car park miles away from where ticket holders are bussed in and, of course, tickets themselves are like gold dust. I have to queue for mine at 7am at an office in Aix where a small quota is offered on the day.

Turning up for my designated tour at 5.30pm, I am braced for an anti-climax. But first I am charmed by the eager and knowledgeable guides, and then by the house itself. It has been preserved as Picasso left it, and though he lived here for only a short period between 1959 and 1962, it is full of intimate glimpses into the life of a legend.

Nothing is cordoned off. In one room a mandolin with a busted string hangs from the wall – the same mandolin that is immortalised in a number of still lifes on view at the current exhibition. On the first floor we see Picasso's bedroom – the bed is small, as was the man. His bathroom, though, is huge and has a wall-sized mural of a faun playing pipes in a forest. Picasso couldn't resist the wet plaster and slammed the scene up with such haste that drips and puddles of paint can still be seen on the terracotta floor.

There is also a presentation of home videos shot by his then wife, Jacqueline. They show a happy old man pottering around his new domain proudly – less the titan of 20th century art, more like Compo from Last of the Summer Wine.

Outside we are lined up next to a grassy mound in the forecourt topped with a huge bronze – Woman with a Vase. Beneath the sculpture, we are told, lie the remains of the greatest artist of the modern era – the creator of some 30,000 works that still mesmerise the world.

The current owner uses the chateau only as an occasional home. As we shuffle out of the property in the translucent light of a perfect Provence evening, I sense an opportunity. Might Madame Huton be tempted to spend a week or two in the bright lights, big city of les rosbifs? If she's up for an asymmetric home swap, my own petit chateau in south-west London is available.

COMPACT FACTS

How to get there

Return fares from London to Avignon with Eurostar (08705 186 186; eurostar.com) cost from £99. Carrentals.co.uk offers car hire in Avignon from £155 for seven days.

Home swap agencies include Home Xchange Vacation (homexchange vacation.com), Homelink International (homelink.org.uk), and HomeForExchange.com.