With their concentrations of mass media, Paris and London are perhaps the prime terrorist targets among European cities. Yet this grim distinction is one of the few things they have in common. The two capitals have always been very different places — and remain so, notwithstanding that the high speed Eurostar rail service has brought them closer together than ever before.

In May of this year Londoners will vote for a new mayor of London. If the forthcoming election is more than usually significant, it is because the frontrunner among the candidates, the former Labour minister, Sadiq Khan, is a Muslim. The London-born Khan has a fair chance of being the first Muslim to become mayor of a major western capital. Even before the Charlie Hebdo massacre and last November’s Paris attacks there was slim chance of a Muslim enjoying such a high civic profile in Paris. (As it happens, there is a current Muslim Mayor of Paris, though the Paris in question is Paris, Texas.)

It would be crass to say that London has coped better with terrorism than Paris. London has not known two devastating terrorist strikes in a single year, as Paris did in 2015. What can be said is that in the wake of the 2005 7/7 bombings Londoners were quick to recognize that the Muslim community was not answerable for the actions of the terrorists. It can perhaps be said, too, that London has embraced diversity to a greater degree than many other cities, including Paris. Encompassing communities drawn from nearly every nationality and ethnicity, it seems at ease with its identity as a hyper-cosmopolitan capital.

It is a striking difference between London and Paris that while London has Muslim enclaves it has no equivalent to the banlieues, the isolated housing estates on the perimeter of Paris dominated by French people of North African heritage. The alienation of the banlieues is exacerbated by France’s vaunted commitment to “liberty, equality and fraternity,” a slogan that for many Muslims rings hollow. What also breeds Muslim disaffection is France’s preoccupation with “laicite,” the rigid separation of religion and state that requires French schoolchildren to display no visible sign of their Muslim identity. Britain by contrast is notorious for leaving things vague and undefined, for “muddling through.” If London’s social cohesion has proved remarkably resilient, it is perhaps because muddle is practically the condition of existence in this sprawling, polyglot, multi-racial megalopolis.

It is not certain that Sadiq Khan will become mayor of London — though his electoral prospects have not been harmed by the habit of the outgoing Conservative Mayor, Boris Johnson, of advertising his own Muslim ancestry in an effort to portray London as the friendliest of business environments. Khan’s main rival, the Conservative candidate, Zac Goldsmith, is perhaps handicapped by the fact that London is a largely Labour city. That Boris Johnson served two successive four-year terms as mayor almost certainly owed more to his popularity as a joshing showman than to his right-wing politics.

In a period of rising inequality, it may not help Goldsmith either, that, unlike Khan, whose father was a bus driver, he is the privileged son of the billionaire financier, the late Sir James Goldsmith.

Khan and Goldsmith are in broad agreement in rejecting the controversial proposal to build an additional runway at Heathrow Airport. But when it comes to spelling out their policies on “security,” the contest between them has the potential to turn ugly, with race and religion poisoning debate. Already Goldsmith, who is himself Jewish, has labelled Khan a “radical” — ostensibly on the grounds that he represents a Labour Party that, under its new leader, Jeremy Corbyn, has swung sharply to the left. Yet who can doubt that Goldsmith is all too alert to the very particular emotive connotations that now attach to the word?

Purporting to be as staunch for London’s rich as for its poor, Sadiq Khan invites the charge of seeking to appear all things to all people. Nevertheless, in these polarized times many must hope that he gets the opportunity to affirm that London’s claim to epitomize 21st century cosmopolitanism is no idle boast.