And in 1974 the Italian architect Tony Facella Senso created Dar Senso in the old medina. The former Italian prime minister, Benito Craxi, was a near neighbour.Most of these houses are still privately owned, and it takes a personal letter of recommendation to get a look. One or two are available to rent, but the rates exclude all but the seriously wealthy: Dar al Qamar, for example, comes complete with servant and cook for a sum in excess of £10,000 a month.Because of the high standard set by George Sebastian, the vision encapsulated in some of these villas is breathtaking, especially those which occupy the eastern wall of the medina and face out towards the Gulf of Hammamet. You can usually spot them from the outside: simple plain white walls, blue-painted doors, traditional cupolas and every kind of antenna, dish and aeriel atop the roof.Fortunately, anyone who wants to get an inside view of life among the 1930s glamour crowd can console themselves with Sebastian’s seminal vision.

The villa that he designed and built with the assistance of a local mason – who used nothing more sophisticated than a series of rods to make his calculations – is open most days and accessible from the Avenue des Nations Unis. Purchased for the state by President For Life Habib Bourgiba, it is now the Centre Culturel International D’Hammamet. Admission costs two dinars, you are free to wander and there is an informal cafe service run by the side of George Sebastian’s marble swimming pool.Until I saw Dar Sebastian I had never seriously begun to ponder the advantages of being a millionaire. The building uses a long marble salon to link two arcaded courtyards. One, the Patio Découvert, has a glass roof with bedrooms off, while the second, larger courtyard is formed round that rectangular pool. There are only two bedrooms, of which La Chambre D’Amis, was intended for guests.

It has fitted wardrobes and an en suite salle de bain with half-sunken marble bath. Chambre de Sebastian, next door, is a suite of four rooms occupying two sides of the Patio Découvert. The master bedroom and dressing room have quite low ceilings for a Mediterranean house, but sport mirrored doors on fitted wardrobes designed by Sebastian himself. Beyond the dressing room is a Roman-style bath with four carved marble thrones, sunk into a central waist-high basin with mirrors running round the room, and beyond this is the boudoir of Mme Sebastian.

The ambience of the whole place is opulent simplicity.I spent an afternoon sitting under the arcades of Dar Sebastian’s 50ft swimming pool which looks out on a dense green garden. Mint tea costs only 1 dinar a cup and affords a fragrant opportunity to imagine Sebastian’s famous guests splashing around in those distant days when Hammamet was by invitation rather than by package tour.. What’s the weather like now? Pretty good, as the north-east monsoon has passed and the approach of winter has lowered humidity and cooled temperatures to the mid-20s, giving sunny days, coolish nights and hardly any rain. The severe flooding that ravaged the Mekong Delta and the Central Highlands this autumn hasn’t reached Hanoi, so the street restaurants are doing a good trade. Walking by moonlight along the central Hoan Kiem Lake is still the city’s favourite pastime.