The G20 vowed Friday to fight cross-border tax evasion by sealing an agreement on joint effort.

The agreement, which commits governments to cooperate in assessing and collecting individual and corporate income, value-added and property taxes, could bring tens of billions in revenue at a time of strong need of more finances for the euro zone.

The world's 20 biggest developed and developing economies (G20) are holding Friday, for the second consecutive day, an emergency meeting in Cannes, France, to discuss ways to deal with the euro zone debt crisis.

The deal is boosting the US and EU effort to force Switzerland and other so-called "tax havens" to put a hold on practices deemed assistance to wealthy people and businesses in hiding income.

Data of the Organization for Economic Cooperation and Development (OECD), which developed the agreement with the Council of Europe, shows the US loses USD 100 B a year and Greece USD 30 B from concealed revenues.

An OECD study in 20 countries found that increased pressure against use of tax havens drove 100 000 wealthy taxpayers to disclose assets and pay taxes in the amount of EUR 14 B, however, about EUR 1 T is still concealed.

"The agreement is meant to promote tax fairness, which might help to ease social tensions that have fueled protests in Europe, the United States and elsewhere. We want the rich to pay taxes. We want the multinationals to pay taxes. That's important in today's environment," said Jeffrey Owens, Director of the OECD's Center for Tax Policy, quoted by international media.

Meanwhile, it was reported that a small group of demonstrators have staged Thursday a rally at the border with nearby Monaco demanding an end to tax havens since the small country is considered one of them.