Speaking in Hong Kong en route to a meeting of G20 officials in Shanghai, French finance minister Michel Sapin said the British public would reject the Brexit and make "the best choice" for themselves and Europe by voting to stay in the European Union in June.
"I believe in people's intelligence," he told reporters.
"Whatever the temptations, tensions or mood changes, they will make the best choice for themselves and for Europe... to stay in the EU."
Sapin said France and Germany in particular wanted to help Britain to make a convincing argument to stay, and he believed the majority of G20 members would also be against a Brexit.
"Our belief is that the best thing for the whole world, for Britain and for the rest of Europe, is that Britain stays within the EU," he said.
The looming vote had led to inevitable economic uncertainty, he added.
"Since it is an election, a referendum, there is uncertainty... That uncertainty is one of the elements that exists today with regard to global
stability or the stability in Europe."
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Britain is to call on G20 finance ministers gathering in China for the two-day meeting to highlight the dangers posed if the country left the
European Union, the Financial Times reported.
British finance minister George Osborne hopes to include an endorsement for Britain's continued EU membership and a warning about the possible destabilizing effects of a Brexit on the world economy in the communique issued by the ministers, who represent 85 percent of the world economy, according to the FT.