The French began voting in a referendum on the European Union's new constitution on Sunday with Europe watching anxiously after final opinion polls pointed to a rejection that could kill the charter. The last surveys put the "No" camp clearly ahead with up to 56 percent expected to vote down the treaty at the end of a heated campaign that divided France and became a debate on the government's economic record as well as the future of Europe, according to Reuters. Polling stations opened at 8 a.m. (0600 GMT) across mainland France, with the weather fine. Around one-in-five voters were left undecided when campaigning ended on Friday. France has almost 42 million registered voters. First exit polls projecting the result are expected when the last polling stations close at 10 p.m. (2000 GMT). The Interior Ministry is expected to issue an official estimate for the result sometime after 11 p.m. (2100 GMT). The constitution was signed by EU leaders last October in Rome after long and tough negotiations. It sets rules for the EU that are intended to make decision-making easier after the bloc's enlargement from 15 to 25 member states in May 2004. The charter requires the approval of all member states to go into force. If it were rejected, the EU would continue to operate under its current rules, but they were designed for a smaller Union and voting could soon become paralysed.