France on Sunday approved the Maastricht treaty on European union by a wafer-thin margin - to the universal relief of its European Community partners.

Britain, the current EC president, immediately responded by calling a special summit meeting of heads of government early next month to consider how to proceed with ratification of the treaty.

In Washington, Community finance ministers expressed the hope that the vote would ease tensions within the European Monetary System, while on the foreign exchanges, the French franc strengthened against the D-Mark.

Early on Monday with all votes counted in metropolitan France and in some overseas territories 50.95 per cent had said Yes and 49.05 per cent No to the controversial treaty on an unusually high turn-out of 70.5 per cent. Not included were votes in overseas possessions west of France where voting began and ended several hours later.

"We have just lived through one of the most important days for the history of our country," said President Francois Mitterrand, in an attempt to soothe the intense divisions opened by the campaign. The result was a "yes for France, a yes for Europe" but there would be neither "victors nor vanquished" from the poll, he said.

The vote was the climax of a campaign which exposed deep divisions over Europe in France, hitherto one of the main driving forces of European integration, and which at times appeared likely to deal a severe setback to the European Community. Uncertainty over the outcome also helped fuel the turbulence on the currency markets in recent weeks, which forced the pound and the lira to be suspended from the EMS.

The result does not, however, mean that ratification of the Maastricht treaty - which provides for political, economic and monetary union between the 12 EC member states, and the establishment of a common currency by 1999 at the latest - is yet assured by the Community's self-imposed deadline of January 1 1993.

Chancellor Helmut Kohl of Germany last night led a chorus of relief among European Community leaders over the referendum result. He vowed to press ahead rapidly with efforts to secure ratification of the treaty in his country and elsewhere, and to work for enlargement of the Community. "The positive result of the French referendum, even if it was narrow, will give the European integration process a new boost in the other member states," he said in a statement.

However, approval of the French referendum result among EC governments was tinged with concern at the narrowness of the outcome and apprehension about the prospects for ratification of the treaty elsewhere in the Community, notably in Britain.

Mr John Major, Britain's prime minister, congratulated Mr Mitterrand on his narrow victory. But he said European leaders now had to consider how to proceed with ratification of the treaty. The summit he had called for early October would need to consider the recent turmoil in the exchange rate mechanism of the EMS. Referring to the narrowness of the French vote he added: "I think we do have to take into account in public debate the many concerns that have been raised throughout the Community over recent weeks."