Next door, in the Royal University of Fine Arts, students have parked their mopeds around a statue of folk musicians, who seem to be serenading the riderless bikes. Out in the street, a vendor passes on a bicycle, hawking his wares through a little speaker with pre-recorded calls that croak out rhythmically, like a bullfrog on wheels.

The city appears determined to wel­­come me back with a musical soundtrack.

I’m skipping the Khmer Rouge horrors this time to revel in the reality of Cambodia’s capital, starting with the commercial frenzy of the Central Market, regarded as the city’s centre point. A mountain of art deco concrete built by the French colonialists in the 1930s, this vast emporium anchors the hub around which Phnom Penh has thrived since Chinese merchants set up in the district, in the 17th century.

In the fish section, strange aquatic beasts writhe in bowls; the textiles depart­ment dazzles with checked krama scarves in various colours; and the electronics section vibrates with cheap gizmos of amazing ingenuity. Electric back-scratcher, anyone? The crescendo comes in the central hall, its gigantic dome of yellow concrete soaring high above jewellery counters, their bargain-basement brooches and watches glittering in fluorescent-lit showcases.

Founded in the 14th century, legend has it, Phnom Penh first became the national capital in the 1440s, following the royal abandonment of Angkor, but it was only after the French seized Cambodia in the late 19th century that it became a solidly built city. The Gallic planning that took hold is best seen in the French Quarter, naturally.

Striding in that direction along Monivong Boulevard – here, the city’s main drag is lined with humdrum businesses devoid of metropolitan glamour – presents another musical interlude. On the pave­ment, a keyboard player tickles his electric keys and a singer warbles a sad song into his mic, two blind buskers at work. I leave them two US dollars richer – the greenback is an official currency in Cambodia, and rather easier to handle than the riel, which runs to several thousand for a cup of tea.

Suddenly the boulevard turns swanky and Shanghaiesque, a brand new glass-walled skyscraper soaring upward. At 187 metres, the Vattanac Capital Tower is far and away Cambodia’s tallest building, a lonely, shiny spike in a poor, low-rise city.

Then another stark contrast: the colonial elegance of Hotel Le Royal, dating from 1929. As a gale blows in, savagely rock­ing a tall traveller’s palm at the entrance, I seek refuge in Le Royal’s polished interior, settling in beneath a whirling fan in the Writer’s Bar, as Somerset Maugham once did.

The storm having died down, I venture next door to the National Library, a build­ing of Greco-Roman severity whose entire contents the Khmer Rouge threw out in 1975. Now restocked with French assis­tance, the library’s 12-metre-high hall harbours only three schoolgirls, studying.

Rambling on towards the riverside, I find the renovated wedding-cake of the Post Office presiding over the tattered remnants of other French colonial build­ings, now turning a riel as laundries, noodle shops and grocery stores. And something seems familiar.

That corner café, yes, it recalls Gérard Depardieu’s seedy bar in City of Ghosts, Matt Dillon’s 2002 neo-noir movie that nailed the ragged anarchy of Phnom Penh 15 years ago. It turns out I’m in the movie’s epicentre, Post Office Square, which is still quite raw, but with islands of reinvention that signal a trendy quartier in the making.

The former police commissariat on one corner is an empty shell, in far worse repair than when it was the grungy, monkey-riddled hotel in which Dillon’s character stayed.

The bare-bones bar on the opposite corner, which Depardieu ran with alcoholic panache as a sleazepit of expat deadbeats, is now a smart restaurant fenced with a hedge. The building housing the restaur­ant was the Manolis Hotel, a first-class hostelry in its colonial heyday that became a dilapi­dated squat after the Pol Pot years but is now being revived, piece by piece. At its other end, a modest Khmer eatery now operates, but above it is the real harbinger of the quartier to come: the first floor is a luxury apartment renting for US$225 a night.

A block away, Sisowath Quay seems to be the city’s favourite park, its grass verge bordering the broad, brown Tonle Sap River all the way down to its confluence with the Mekong. A ragtag bunch of citizens, the Sunday afternoon crowd, are taking their time, pestered by a woman toting a tray of fried bugs and other vendors. Riding along the river’s 45-degree concrete banking, a 10-year-old on a little bike keeps everyone enter­tained – one slip and the little daredevil would tumble down into the muddy depths.

Behind its high wall, the Royal Palace shelters from this demotic scene. Inside is an oasis of calm and order, a staggering island of privilege amid a city of great poverty. Mostly erected in the early 20th century and set among lawns, the palace’s steep-roofed halls are Thailand lite; the same forms but far less ornate, even at its sacred jewel: the Silver Pagoda, with its floor of solid silver tiles.

As a flock of boy monks is shepherded along by two elders in a drift of saffron robes, the percussive chimes of classical Khmer music begin to sound. They draw me towards the exit, where a five-piece combo is tapping on wooden xylophones and brass gongs. The polyrhythmic beauty of the music is mesmerising, even as the drummer keeps time with one hand while tapping at his smartphone with the other.

It’s a metaphor for Phnom Penh, a city segueing from time-worn ways into modernity, without missing a beat.