The EU constitution
The victory for the no vote - 55 percent to 45 percent - came in a nationwide referendum on the European Union constitution after a bruising campaign that divided France and alarmed Europe.
Foreshadowed in recent polls, the no vote could doom the 448-article treaty because all 25 members of the European Union must ratify it before it can take effect.
The rejection could signal an abrupt halt to the expansion and unification of Europe, a process that has been met with growing disillusionment among the wealthier European Union members as needier countries like Bulgaria and Poland have negotiated their entry.
President Jacques Chirac, who had predicted France's isolation in Europe if the constitution was rejected, smiled stiffly as he struggled to mask his disappointment.
"The decision of France inevitably creates a difficult situation for the defense of our interests in Europe," he said in a brief statement broadcast live on television. Hinting at possible cabinet changes, he added, "I will tell you in the very next days my decisions regarding the government and its priorities."
Early this month, Mr. Chirac had vowed not to change his government if the referendum failed, saying it was "neither a plebiscite nor a moment of political change."
But the vote, which made France the first country to reject the treaty, has deeply wounded the French president. More than 50 years ago, France was a founding member of the six-country precursor to the current European Union. Mr. Chirac had assumed that through the constitution, a document similar in some ways to the Constitution that binds the United States, France could promote a stronger, more unified Europe that could project not only economic but also political power around the world. He repeatedly spoke of a "multipolar world" with Europe as one of the poles counter-balancing the United States.
After the vote, some extreme opponents of the constitution called for Mr. Chirac to resign.
"We are tonight before a major political crisis," said Philippe de Villiers, head of the right-wing Movement for France and a vocal lobbyist against the constitution. He added that Mr. Chirac had two choices: resignation "given the fact that he had been so personally involved" or the dissolution of Parliament.
Jean-Marie Le Pen, the head of the far-right National Front, faulted Mr. Chirac for threatening the French with "chaos" if they voted no, adding, "He isn't qualified, it seems to me, to remain as the head of the country."
About 70 percent of France's registered 41.8 million voters cast ballots, a high turnout on a Sunday that was also Mother's Day here. Throughout the day in Paris, electronic billboards all across town said: "Don't let the others decide for you. Go vote."
Pollsters said the rejection reflected French voters' anger at the 72-year-old president and his center-right government for failing to improve the country's troubled economy, as well as fear that the treaty would erode France's generous cradle-to-grave social safety net.
The debate had been colored by fear of the mythical "Polish plumber," the worker from recent European Union members from the East who is increasingly free to move West and willing to work for lower pay than Frenchmen.
Proponents of the "no" fueled voters with fear of a more powerful European Union where France no longer has influence, and of an increasingly "Anglo-Saxon" and "ultraliberal" Europe where free-market capitalism runs wild.
France's rejection makes it more likely that the Netherlands, where polls show that 60 percent of voters plan to reject the constitution, will vote no in the referendum there on Wednesday. Nine other European Union members have approved it.
The Dutch prime minister, Jan Peter Balkenende, called on voters to approve the constitution despite France's rejection, saying: "There is all the more reason to say yes so that some progress can be recorded with the constitutional treaty. Each country has its own responsibility."
French supporters and opponents of the new EU constitution have held final rallies ahead of Sunday's vote.
German and Spanish leaders threw their weight behind the "Yes" campaign in two Socialist Party gatherings.
But leading Socialist dissenters joined with Communists and union leaders in Paris to urge a "No" vote.
Germany's parliament completed the ratification of the charter on Friday, with an upper house vote designed to boost France's struggling "Yes" camp.
Latest opinion polls have provided mixed messages, one suggesting support for the "No" campaign had fallen to 52%, another that it was up to 56%.
Campaigning ended at midnight local time (2200 GMT) on Friday before the Sunday referendum.
Shift uncertain
Both the governing centre-right UMP party and the opposition Socialists urged voters to support the proposed constitution.
In picturesOn Friday evening, Socialist party chief Francois Hollande welcomed Spanish Prime Minister Jose Luis Rodriguez Zapatero at a rally in the northern city of Lille.
"Europe needs France, its enthusiasm, its culture, its strength and its momentum," he told a crowd of about 3,000 people, adding that the "No" campaign was "sad and pessimistic".
At a smaller gathering in the southern city of Toulouse, German Chancellor Gerhard Schroeder asked the French to vote "Yes" with their hearts and their heads.
Several hundred people gathered for a "No" rally in Paris, organised by various left-wing parties and trade unions.
The BBC's Sarah Shenker at the rally says the "No" campaigners are already contemplating how to use the political capital they might gain from victory.
Socialist dissenter Henri Emmanuelli denied that the campaign was negative.
"'No' is not the end of something, it's the beginning of something, it's the beginning of a great hope," he told the crowd.
Far-right National Front leader Jean-Marie le Pen, who also backs the "No" campaign, addressed a public meeting in the south-eastern town of Villeneuve-Loubet.
Ratification votes
On Thursday President Jacques Chirac went on TV to call for a "Yes" vote, which he said was vital for the future of both France and Europe.
Watch the TV plea
And one of the main architects of the constitution - former French President Valery Giscard d'Estaing - made an emotional appeal to the people of France in a speech to the German parliament just before its vote on Friday.
The campaign has been overshadowed by a gloomy mood brought on by years of faltering growth and unemployment of around 10%.
Treaty rejectionists are also ahead in the Netherlands, which will hold its referendum on Wednesday.
The EU constitution has to be ratified by all 25 member states to become law.
France is the second EU member to hold a referendum on the document. Spain's referendum resulted in a "Yes" vote, which was then ratified by both houses of parliament.
The treaty aims to streamline decision-making in the enlarged EU of 25 nations.