Almost every economically literate Frenchman was against the 75 per cent supertax that Francois Hollande imposed on high earners in 2012.

The president believed it would generate huge revenues, reduce deficits and drive growth.

He was wrong.

After the tax was introduced, government revenues were an astonishing €14 billion (S$21.2 billion) below expectations in the following year. The disastrous tax scheme was quietly dropped last year.

I mention this as a warning of the dangers of going after rich people through punitive measures.

Football is a case in point. Top players are footloose and can easily move from the Premier League to La Liga or Serie A.

So when a government attempts to impose super-high marginal rates, it is not the exchequer that enjoys the benefits, but football clubs from other nations.

It's worth saying something else, too. Footballers are not rich because they are greedy or somehow dubious, but because they are so widely valued.

They make their money through a voluntary exchange, just like everyone else in a free market, such as inventors, businessmen and entrepreneurs.

The wealth of footballers emerges as a direct consequence of millions of people from around the world choosing to pay relatively small amounts to watch them in action.

Every exchange is a positive sum. No footballer has coerced anybody; they have merely worked their socks off to reach a level of skill that people from sub-Saharan Africa to China choose to watch.

Football is a community institution as much as it is a commercial one. It is one of the things that binds us together, a thread in the social fabric.

And yet this doesn't alter the value that football creates through mutual exchange, or ameliorate the dangers of trying to thwart high earnings through arbitrary means.

Indeed, schemes such as a maximum wage (that once existed in football) would have profound unintended consequences, inviting top players to go overseas, undermining the quality of the Premier League, thus driving down its welfare contribution to society.

But this brings a caveat. We can be relaxed about the high earning of footballers (and aware of the dangers of trying to tax or regulate them out of existence), but shouldn't we also insist that they pay back into the society that helped them to become rich?

The aggressive tax structures used by some top players, revealed over the past two weekends by The Times of London, indicates a troubling, if morally complex, problem.

Leaked documents relating to Ander Herrera of Manchester United, and Cesar Azpilicueta of Chelsea, for example, showed that "players can halve their tax on earnings from image rights by using companies and ingenious tax arrangements, saving hundreds of thousands of pounds".

Herrera will save £609,320 and Azpilicueta £138,860 by using their accountant's shell company rather than paying income tax.

Manchester United manager Jose Mourinho, who denies wrongdoing, may be put on trial for a different set of arrangements allegedly involving a sequence of companies from Ireland and New Zealand.

Now, one can understand why people wish to legally minimise their tax bill (the familiar distinction between avoidance and evasion).

But anyone who has listened to a slick accountant run through bewildering offshore structures, loan-back arrangements and the wider panoply of ruses to avoid paying money to the exchequer will have been troubled by the morality, if not the legality, of behaviour designed to exploit loopholes.

I doubt that many of the top footballers are fully aware of what their agents and accountants are up to, but the covert nature of the offshore tax industry is bringing wealth itself into disrepute.

That is why footballers should instruct their agents to avoid the offshore tax racket.

By gaming the system, even within the letter of the law, they are undermining public confidence in the value of wealth creators.

It is often said that punitive tax rates drive high earners towards tax avoidance.

In fact, it is aggressive tax avoidance that stokes the public appetite for punitive taxation.

THE TIMES, LONDON