French voters have rejected the European Union constitution in a key referendum.
The BBC News website explains what happened, and what is at stake for France and the EU.
What consequences does the French "No" vote have?
The constitution, which is a treaty between 25 states, cannot come into force unless it is ratified by all of them. So a French "No" means the constitutional treaty, in its current form, is almost certainly dead.
Experts say France is unlikely to vote on the constitution again, as Ireland did with the Nice treaty, approving it at the second attempt.
They say two other scenarios are more likely:
(a) that EU leaders will attempt to salvage some parts of the constitution, by introducing them in other ways, for example by agreement among heads of state
(b) that a new, cut-down version of the treaty will be drawn up, containing the key changes to the EU's decision-making process and other essential clauses - and that a new attempt will be made to ratify this shorter, and less controversial text
French President Jacques Chirac warned voters before the poll that France's influence in the EU would be severely weakened if they rejected the constitution.
However, one possibility is that the failure of the constitution could stimulate the creation of a "core" group of countries, including France, that would seek to integrate more quickly and deeply than the rest.
Will other countries still continue to ratify the constitution?
The Netherlands is still expected to hold a referendum on Wednesday. Polls there give the "No" side a lead of up to 20%.
Luxembourg's Prime Minister, Jean-Claude Juncker, has said that the ratification process should continue throughout the EU, even if there are "No" votes in France and the Netherlands, so it is likely that Luxembourg will hold its planned referendum in July.
However, a summit of EU leaders on 16 and 17 June could call a halt to the ratification process.
The UK has said it will not hold its planned referendum, due in 2006, if there is nothing to vote on.
If a broadly Eurosceptic country like Denmark or the UK rejected the constitution, this might not give the EU such a powerful shock as a "No" in one of the six original founding states, such as France or the Netherlands. However, it would still prevent the constitution becoming law - unless either country decided to withdraw from the EU, which is unlikely.
Nine countries have so far ratified the constitution.
Can the EU manage without a constitution?
Yes, it would just continue operating on the existing set of rules. However, many experts say the failure of the constitution could cause a grave crisis within the union, leaving it divided, confused and condemned to a period of stagnation. Plans for further enlargement could be put on hold.
Will the result bring political changes in France?
It is widely expected that President Chirac will sack Prime Minister Jean-Pierre Raffarin.
Mr Chirac has said he will not resign himself.
The referendum campaign has shown the Socialist Party to be completely divided, and, if anything, in greater disarray than when it lost the first round of the presidential election in 2002.
Had the French result been predicted?
Yes, in the final days before the vote, polls gave the "No" side a lead of up to 10%. However, when President Jacques Chirac first named the date of the referendum, the "Yes" side was well in the lead, with about 60%.
Campaigners for a "Yes" vote had hoped, until the last minute, that they would be able to persuade the 20% or so of the population who were undecided.
Why did so many people vote "No"?
One reason is that the government and president are unpopular - unemployment is running at 10% and the economy is in the doldrums. The result can be seen in part as a protest against the government.
On the left, many voters believe that the constitution would create an ultra-free market economy within the EU, that would undermine traditional French levels of social protection, and allow countries with cheaper labour costs to take French jobs.
On the right, voters were concerned that France is ceding too much sovereignty to the EU.
Some voters were also troubled by the decline of France's influence in the EU, as a result of enlargement, and the plan to start membership talks with Turkey later this year.
Did voters know what the constitution says?
The French government distributed 46 million copies of the constitution to French voters in the last two weeks of May. At the same time, polls showed the size of the "No" vote increasing.
Before the copies of the text were sent out, two-thirds of voters described themselves as poorly informed. High levels of ignorance were also recorded when Spanish voters backed the constitution in a referendum in March.
Who headed the "No" campaign?
It was a grassroots movement without any one dominant figurehead. A number of prominent Socialist Party members, including deputy leader Laurent Fabius, defied the party leadership by backing a "No" vote. The Communist Party, some Greens, unionists and the anti-globalisation movement were also in the "No" camp.
CHANGING FRENCH ATTITUDES
4 March: Voting date named14 April: Chirac TV debate28 April: Socialist ex-PM Lionel Jospin backs Yes in TV interview3 May: Chirac TV address16 May: Campaigns start
29 May: Referendum day
On the right, nationalists such as Jean-Marie Le Pen were against the constitution, and there were some rebels within the (pro-European) governing centre-right party, the UMP.
Polls suggested that most "No"-voters are left of centre. One poll found that 75% of respondents who described themselves as working class, said they would vote "No". Farmers are also mostly sceptical.
Employers, elderly voters and graduates were thought to be the categories most likely to vote "Yes".