Czech President Vaclav Klaus has been holding out on the treaty
EU leaders meeting in Brussels have agreed a deal designed to win Czech backing of the Lisbon Treaty, clearing a major hurdle to its ratification.
The Czechs were granted an opt-out from the EU's Charter of Fundamental Rights, similar to that of the UK and Poland.
Czech President Vaclav Klaus was satisfied with the concession, Czech PM Jan Fischer told reporters in Brussels.
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"The road to ratification stands open," said Swedish Prime Minister Fredrik Reinfeldt, whose country holds the EU's rotating presidency.
The Czech Republic is the only one of the 27 EU nations not to have ratified the treaty, which aims to streamline decision-making and bolster the bloc's role on the world stage.
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The BBC's Oana Lungescu in Brussels says Mr Klaus - an ardent Eurosceptic - had feared that without the opt-out, the charter would allow thousands of ethnic Germans who were expelled from Czechoslovakia after World War II to reclaim their lands.
"Vaclav Klaus was content with the text. He has been informed about all modifications... and does not have a problem with it," PM Fischer said after EU leaders agreed on the text at a summit.
But there is one final legal hurdle to Prague's ratification - the Czech Constitutional Court is expected to rule next week on whether the treaty complies with the country's constitution.
Presuming the court dismisses the latest challenge to the treaty, the Czech prime minister said his country could ratify the treaty by the year's end.
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European Commission President Jose Manuel Barroso said the eight long years of negotiating the treaty reminded him of a "marathon with hurdles".
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Mr Reinfeldt called on EU leaders to agree a "fixed sum" that would open the way for other rich donors, like the US and Japan, to make similar aid pledges to help developing nations cope with the effects of climate change.
But Polish Finance Minister Jacek Rostowski told the BBC that nine Eastern European nations were prepared to block a deal unless richer countries paid a larger share of the costs.
EU sources said the presidency would present new proposals on Friday, the last day of the summit.
The EU is committed to cutting greenhouse gas emissions by 20% by 2020 and by up to 30% if other countries join in.
The European Commission has recommended EU nations pay up to 15bn euros ($22bn; £13bn) a year from 2013 to developing nations to help them cope with the effects of climate change.
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