Sarkozy said earlier on Wednesday that the current proposals for an accord at the G20 summit did not satisfy France and Germany and that tougher regulations were a "non-negotiable goal".
The two leaders' comments came a day before the meeeting in the British capital, which is likely to focus on how to deal with the worst global recession in 80 years.
Earlier on Wednesday, Barack Obama, the US president, called on the international community to "pick up the pace" in an effort to tackle the global economic crisis.
Speaking at a news conference with Gordon Brown, Britain's prime minister, in London, he said: "We can only meet this challenge together".
Obama spoke out against protectionism and said nations must not repeat the mistakes made during the Great Depression of the 1930s.
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While he wants G20 member states to inject more money into programmes aimed at kickstarting their flagging economies, France and Germany have said that greater regulation of the financial markets is a more pressing need.
Rob Reynolds, Al Jazeera's senior Washington correspondent, said: "Obama does want increased spending. He has been talking about putting together a big stimulus package, as the US and China have already doned.
"It looks, however, that he has scaled back considerably on his expectations for receiving any commitments on specific figures at the London meeting."
Despite the tensions over how to tackle the crisis, Sarkozy said he had "confidence" in Obama.
Obama later met Hu Jintao, the Chinese president, and said he had accepted an invitation to visit China later this year.
The White House said Obama and Hu had agreed to "intensify co-ordination and co-operation on global economic and financial issues".
The two countries also agreed to form a US-China Strategic and Economic Dialogue group.
Hillary Clinton, the US secretary of state, and Timothy Geithner, the country's treasury secretary, will represent the US during those talks.
Obama also met Queen Elizabeth II at Buckingham Palace, hailing what he called an "extraordinary affinity and kinship" between the people of the US and Britain.
Accompanied by his wife Michelle, he said he valued "what the queen stands for", including "decency" and "civility".