Guccio Gucci, a craftsman in leather, left Florence for New York in 1953. Here he taught sophisticated Americans to wear his signature loafers. Now, in one of the most inequable of history's cultural exchanges, less sophisticated tourists are returning the footwear compliment. Trainer-clad crocodiles of what, with the pomp of the Medici, the Florentines call maleducati, dominate a streetscape where the Corsini and della Gherardesca families invented banking while the tradesmen they employed busily created the Renaissance from the proceeds.
The degradation of Florence by low-value tourism is a politically delicate subject, but now openly debated, Florentines being no strangers to conflict. There's no better place to view the problematic dynamic than the terrace of the Gucci Caffè on the glorious Piazza della Signoria, the old town hall square. With my affettato misto of Tuscan salumi and spaghettini with bottarga and a little vernaccia served by model-gorgeous waiters with fashionable undercuts and pony tails, I feel safely in the high-value traveller demographic.
On my left, David and Neptune. Across the square, the less majestic reality of a heartbreakingly beautiful zombie city. It is full of shuffling lines of the incurious committed to an irksome itinerary not of their own making. The problem in making that comment is the risk of appearing a heartless, ultramontane exclusivist. But no one who has seen the queues at the Uffizi or the Duomo and sensed the footsore despair of the critically bored can maintain even a fragile grip on the idea that art is uplifting. And, picking my way over smeared polystyrene boxes, I find myself thinking that's a deplorable thing to remark in the sublime City of Flowers. I can't claim direct access to the Spirit of Brunelleschi, but I doubt he'd be much pleased by a return to the tourists' Florence of today.
I ask my host, Costanza Menchi of the Osservatorio dei Mestieri d'Arte, an organisation dedicated to local artisans, what's to be done about tour buses and the deadly trail of litter-stuffed bins they leave behind. Her answer – and her organisation is backed by 11 banks – is to encourage visitors who might thoughtfully engage, for example, with the real-world activities of existing artists and craftsmen.
This was later echoed by James Bradburne of the Palazzo Strozzi, the stupendous pietra serena villa where he curates highly intelligent art exhibitions and guides the cultural politics of Florence with a firm Medici-like hand. "We want people to visit Florence for longer and more deeply," he says. And adds: "We do not encourage the first-time tourist." Bradburne wants "a city worth re-visiting". The contemplative, respectful visitor who returns for more? This is as radical a re-vision as the invention of perspective.
So, what is the alternative Florence for the thoughtful visitor? My first visit was to the Antico Setificio Fiorentino, a glorious working silk mill in the same premises on Oltrarno (the other side of the river) since 1786. The banging and rattling noises are hypnotic and impressive, an industrial scene of charm and glamour which reminds us of what we have lost. The warping machine, an orditoio, is made to a design by Leonardo da Vinci. And it still works.
But this is not a theme-park factory, it is a real business. The Setificio feeds the international interior design trade with its beautiful stuffs: FedEx picks up often for Jacques Garcia in Paris and Peter Marino in New York. Sample boxes are marked "Hicks" and "Mlinaric", living and dead gods of interior design. And since fashion entrepreneur Stefano Ricci acquired the silk mill in 2000, its products now furnish hyper-yachts and Gulfstreams. You find its filaticcio, a heavy linen silk mixture, in picture-perfect Tuscan country houses.
But another insight short-circuited 500 years of history. They showed me bolts of the astonishing shot taffeta known as Ermisino. This is a fabric so perfect it stands up for itself. Yank a length off the roll and it becomes a tectonic shape. If you want to understand Renaissance art, you would simply wrap a beautiful – I think probably naked – woman in Ermisino and try to paint the falling of light on jagged, reflective crimson.
Maurizio Bonas, the Setificio's director and a passionate advocate of local manufacturing in the face of politicians' obdurate and destructive globalisation, asked: "Why should there be a difference between a museum and a factory ?" I do so agree.
Next, Aqua Flor, a three-year-old perfumery where the proprietor offers customers an introduction to authentic Florence which he nicely glosses as sex, style, craft and luxury. Appropriately for a business that has its roots in Renaissance spagyria, an alchemy with vegetables, Selino Chelino dresses like a magus, a sad wizard drenched in charm and posh scent. In a darkly romantic consulting room which makes no concessions to modernismo, he holds a bottle of his scent called Duende with a respectful grace appropriate to a product costing €1,800 for 100ml.
There is theatre here, as he spritzes me with its swooningly intense perfume, but there is business sense too. Aqua Flor sells only in Florence. You can't buy it online, nor is there any distribution. Meanwhile, nice modern touches include a plan to put floral fragrance into the water they use to clean the streets, as well as a bespoke product for Tonino Lamborghini. It smells like an expensive sportscar.
The Scuola del Cuoio is a leather school in the gardens behind the apse of Santa Croce. A student recently started the fine pointy-shoe store called Stefano Bemer. The benchmark for Florence's calzature di lusso is the astonishing Museo Salvatore Ferragamo where you'll see what art can do to leather. Or on to Bianco Bianchi's shop on the Via Maggio, in the Oltrarno's antiques area. Here they work the moonstone scagliola in traditional patterns that, for good or bad, inspired Gianni Versace.
I especially enjoyed visiting Alessandro Dari. In the mornings a suburban pharmacist, he returns to his magnificent Renaissance tower in the afternoon to craft elaborately narrative jewellery to the sound of Yo-Yo Ma. There has been a tradition of grottoes in Florence since Buontalenti's bizarre fantasy in the Boboli Gardens and Dari has created one in his own shop.
But there are also parts of official Florence that are not fatigued by the wrong sort of tourism. The Corridoio Vasariano is a kilometre-long secret passage that runs above the peddlars and gawpers on the Ponte Vecchio. Commissioned by the Medici so that they could avoid the maleducati of the day while strolling from the Uffizi to the Pitti between cocktails and Vespers, it is not open to the public. However, there are specialist guides, Boutique Florence for example, who can sometimes negotiate a visit. The corridor is lined with self-portraits of mostly second-order artists, adding a special flavour to the already spectral atmosphere.
You can eat very badly in Florence, but you can eat extremely well if guided. Start with breakfast at Gilli, the famous 1733 caffè on the Piazza Repubblica. Stand at the bar in the brown wood and glass interior to be served by waiters with the grace of Donatello and the severe authority of a Pope. The price of a superlative latte is less than Starbucks while the experience is priceless. By contrast, the Borgo San Jacopo in Ferragamo's Lungarno Hotel has views and food appropriate to its prestige and there can be complaints about neither, although the style is Euro-smart rather than artigianale. For artisan food, go to Fagioli, ignore the menu and wait for them to bring you pappa alla pomodoro, ribollita, ravioli with chestnuts, and a fiascho of the purple chianti that time forgot.
Lunch at restaurant 'ino, in an Uffizi back-street? Here is a boldly reinvented paninoteca: jostling, but very good. Or a simple plate of cheese and an interesting range of wines at Volpi e l'Uva? This trip ended with brunch at Se.sto, so called because it is a modern penthouse on the sixth floor of the old Excelsior Hotel. This you enter from the quiet and lovely Piazza Ognissanti with the Umiliati's church and its della Robbia-style lunette.
The view is simply the best in Florence – a grand prospect of the Arno to one side, a vista of terracotta pantiles to the other, magnificently interrupted only by the stately presence of Brunelleschi's ineffable Duomo. Amazingly, here you can appraise it at eye-level. As if to illustrate the new Florence, Se.sto's cook is Albanian.
It is as difficult to see Florence afresh as it is New York. In one place, everything looks like a movie. In the other, everything looks like a page from E H Gombrich. And there are paradoxes. Sileno Cheloni, the genie of perfume, had mystically asked: "What does Florence smell like ?" Next day he was spotted in a grungy kebab joint. So he already knew one of the answers. And, say what you like about the divine Michelangelo and his influence, but one hundred metres from San Lorenzo and the Medici Chapels, rubbish pizzas take over.
The true Florence? Forty-three years after my first visit as one of the unhygienic backpacking maleducati, I am still unsure. Maybe it is something as elusive as Dante's vision of Beatrice on the Ponte Santa Trinita: the unattainable and the ungraspable. But here's the thing, I always re-visit.
British Airways (0844 493 0787; ba.com) will also start flying from London City from 31 March. Pisa airport is served by a variety of airlines from the UK.
Boutique Florence (00 39 392 914 2810; boutiqueflorence.com). Full-day tours €150 (£127); private tours of the Corridoio Vasariano €400 (£338).
Antico Setificio Fiorentino, Via Lorenzo Bartolini 4, Oltrarno (00 39 055 213861; anticosetificiofiorentino.com).
Aqua Flor, Borgo Santa Croce 6 (00 39 055 2343471).
Bianco Bianchi, Via Maggio 4R (00 39 0552658257; biancobianchi.com).
Museo Salvatore Ferragamo, Via del Tornabuoni 2 (00 39 055 35621; museosalvatoreferragamo.it).
Alessandro Dari, Via San Niccolo 115R (00 39 055 24 47 47).
Eating & drinking there
Gilli, Via Roma 1R (00 39 055 213896; gilli.it).
Ristorante del Fagioli, Corso Tintori 47R (00 39 055 244285).
Le Volpi e l'Uva, Piazza dei Rossi 1 (00 39 055 2398132; levolpieluva.com).
'ino, Via Georgofili 3R (00 39 055 219208; ino-firenze.com).
Se.sto, Piazza Ognissanti 3 (00 39 055 27151; sestoonarno.com).