Even after donating his estimated 800,000-euro ($1 million) monthly salary to charity, Paris Saint-Germain new signing David Beckham will still be in the money.

-- How much is "Brand Beckham" worth?

According to Forbes magazine in April 2012, Beckham, 37, was the highest-paid footballer in the world with $46 million a year, just ahead of Cristiano Ronaldo of Real Madrid ($42 million) and Barcelona's Lionel Messi ($39 million). The Sunday Times Rich List said he had a net worth of £190 million last year

The face of clothing retailer H and M, sportswear manufacturer Adidas and electrical giant Samsung, Beckham is the eighth-highest earner in all sports but unusual in that the majority of his earnings -- $37 million -- came from advertising contracts.

- Has he given up some of his image rights to PSG?

Probably. This practice, uncommon in France, is widespread in England and Spain, where Beckham played for Manchester United and Real Madrid, and involves players giving a share (often 50 percent) of advertising earnings to a club in exchange for a higher salary.

The share given to the club only involves contracts signed after the player has put pen to paper. In practice, Beckham will continue to receive most of the advertising earnings on his contracts with H and M, Adidas and Samsung but will give to PSG half of any contract he may sign in the next five months.

In France, Yohan Gourcuff negotiated such a contract when he joined Lyon, which was disastrous for the club, who paid him an enormous salary (480,000 euros a month) in the expectation of advertising returns which never materialised.

At PSG, Zlatan Ibrahimovic is likely to have such a clause in his contract.

- How much is Beckham likely to benefit from any profits PSG might make by using his image?

Every player earns royalties on products based on their image or name.

"After that, it's a question of negotiation," said Franck Hocquemiller, a football image agent. "The market price is between 10 and 20 percent. Are we talking about profit margin or revenue? In Beckham's case there's no reason it would be less than 20 percent logically on the revenue PSG gets on its products. That could be huge."

At 110 euros per replica jersey, Beckham could get a minimum of 10 euros given that he helped sell one million replica shirts with his name on them during his four years at Real Madrid from 2003 to 2007.

- Are there any tax implications for his plan to donate all his salary to charity?

Not really. At least not anything sufficiently significant to explain the gesture. Giving his estimated 800,000 euros a month to charities that help sick children would certainly make him eligible for a reduction in tax on the rest of his earnings but the tax ceiling for charitable donations is fixed at 20 percent of overall revenue.

"He'll certainly pay a bit less tax but it (the donation) is above all a good PR stunt," said Hocquemiller. "He's arriving in a country in a financial crisis and this is how he is trying to silence his detractors."

Whatever happens and taking into account his additional revenue sources in his overall earnings, Beckham won't be paying completely for free at PSG.

- Have PSG and Beckham achieved the perfect marketing coup?

Pretty much, although the length of Beckham's contract is the only sticking point, as it gives PSG only five months to exploit his image to the full through replica kit and other items for supporters.

"Five months is very short," said Hocquemiller. "A 12 or 18-month contract with a get-out clause after six would have been more comfortable. This really seems like short-term marketing."