French President Jacques Chirac has made a dramatic last-ditch televised plea for a "Yes" vote in Sunday's referendum on the EU constitution.
Mr Chirac said a "No" vote would be a serious blow to the EU
Trying to buck the "No" trend which polls indicate, Mr Chirac urged voters not to use the referendum as a vote against the government.
It was a vote for the future, he said, adding that Europeans would see a French rejection as a "No" to Europe.
The EU constitution has to be ratified by all 25 member states to become law.
The latest opinion poll, by TNS Sofres-Unilog, shows the "No" camp on 54%, with "Yes" on 46%.
France is the second EU member to hold a referendum on the constitution. Spain's referendum resulted in a "Yes" vote, which was then ratified by both houses of parliament.
'Destiny in your hands'
Mr Chirac gave a brief but heartfelt performance, with the flags of France and Europe clearly visible behind him.
He said the vote was vital for the country's future.
"On Sunday each one of you will have in his hands part of the destiny of France," he said.
"We must not mistake the question," he added. "It is not about saying yes or no to the government. It is about your future and that of your children, of the future of France and the future of Europe."
But he hinted that the government's popularity was an issue and that he might sack Prime Minister Jean-Pierre Raffarin, saying he would give a "new impetus" to policy.
He said Europe faced stiff economic competition from the US and Asia and had to defend its values.
A vote against the treaty would be a serious blow to the EU, he added.
"It would open a period of divisions, doubts, uncertainties,"he said. "It's an illusion to believe that Europe would pick up better than ever with another project. Because there is no other project."
Mr Chirac tried to calm fears of an attack on France's social model, saying it would be protected from any savage economic free-for-all within the union.
The French president also gave an assurance that the people would be consulted in a referendum over whether to allow Turkey entry to the EU.
Eleven successive polls have shown a clear lead for the "No" camp in France.
The "No" camp has united disparate aggrieved groups
Treaty rejectionists are also ahead in the Netherlands, which will hold a referendum on 1 June.
The BBC Paris correspondent says some voters want to protest against the centre-right government, but many others fundamentally object to a constitution they think will destroy the social benefits that French society has accrued over the years.
The treaty is aimed at streamlining decision-making in the enlarged EU of 25 nations.
A leading opponent, former Socialist Prime Minister Laurent Fabius, urged voters to turn out in force in Sunday's referendum.