CAN beauty be stifling? Paris puts that proposition to the test, a city manicured to perfection that has confined its immigrant underclass to the invisible suburbs and burnished every surface of its seductive allure.

Certainly, a lot of young Parisians have voted with their feet, moving across the Channel to Paris-on-Thames, aka London, where they come not so much in search of jobs – although there have been more of them – as of the global swirl: that raucous mix of innovation and grunge missing in a too-perfect Paris.

A new lycee, a new radio station (French Radio London) and a new electoral constituency including Britain all testify to the exodus, as did the appearance here last week of the French Socialist candidate Francois Hollande, otherwise known as “Monsieur 75 percent”: more on that below.

Nobody knows exactly how many French people have moved – as European Union citizens they don’t need to register – but more than 300,000 now live in London, making it the sixth-largest French city. Most are under 40. They learn English and they learn that globalization is not merely the catalogue of woes so laboriously laid out by the French left over the past couple of decades.

They feel, of a drizzly afternoon in Shoreditch, the mysterious tug of energy over beauty and of edge over elegance.

Hollande came to make his pitch to this expat crowd before the French presidential election next month. He was snubbed by David Cameron, despite the fact the British prime minister was snubbed recently in Brussels by President Nicolas Sarkozy: European leaders, in self-congratulatory mood over a few weeks without an outright euro crisis, are now banding together to avoid any disruption – a Hollande victory, for example – to Mario Draghi’s silky euro salvage operation.

Otherwise, however, Hollande was well received. There’s a thirst in Europe for growth, for something other than Franco-German austerity, and for a comeuppance for all those bankers seen as the villains of an age of inequality.

Hollande has made speculative finance his prime target. “I wanted to come here to London to say that finance must be in the service of the economy to create wealth and not to enrich itself on the real economy,” he said.

Nobody sensible would argue with finance serving the economy rather than a few financiers. But Hollande’s new proposal to impose a 75 percent marginal tax on incomes above 1 million is populist politics at its worst. He declared on Jan. 28 that imposing hypertaxes on the very rich backfires. “A punitive tax on a tiny fraction of taxpayers would not produce much revenue,” he said.

Hollande was right in January and wrong now. His flip-flop, although it seems to have given him a slight boost in the polls, raises again the temperament question.

Hollande is a highly intelligent and cultured man, but is he a waverer? He managed to spend years not reforming the French Socialist Party at a time when the rest of the European left was busy ditching class struggle to adjust to the demands of modernity and globalization.

A 75 percent tax, added to other taxes and social charges, would mean taxing the rich at over 100 percent. A lot of the wealthiest French people have already moved. Those that have not would.

The power of voting with your feet is evident in London, a city that has found strength in flux while Paris has gilded its stasis. Hollande needs to personify a new French left that will not punish creators of wealth even as it calls for growth: His proposal does the opposite.

The French election remains too close to call. Sarkozy faces some of the same problems as Barack Obama. There are the surface ones: high unemployment, faltering growth, budget deficits. And then there is the core issue: Neither has found a way to connect with the nation in a manner that lifts the mood or creates a conviction of better days to come.

That’s a tougher task in France, whose reflex mode is grumpiness, than in the United States, where can-do optimism is the baseline.

Still, the French like the Americans have kept their distance from their president. In France, with Sarkozy, it’s a question of perceived vulgarity.

In the United States, it’s a question of perceived aloofness.

Somewhere beneath those perceptions lie deeper prejudices.

So, in theory, Hollande should be a shoo-in. He wants to be seen as “Monsieur Normal.” I don’t think being “Monsieur 75 percent” helps. It puts him out on a limb. He wants to come across as a man of the people in touch with “la France profonde,” the deep France repelled by Sarkozy’s “bling-bling” lifestyle.

But France has changed, as the big migration across the Channel suggests. And the “Merkozy” euro salvage operation has kept Europe from disintegrating before the generation of idealistic new Europeans living in Paris-on- Thames takes the reins. Score one for messy improvisation over beautiful order.