French voters are choosing their next president after an unpredictable campaign that has divided the country.

The second round contest pits centrist Emmanuel Macron, a 39-year-old former investment banker, against the far-right nationalist Marine Le Pen, 48.

The vote is being closely watched across Europe, as the results could affect the future of the EU.

The polls opened in metropolitan France at 08:00 local time (06:00 GMT) on Sunday and close at 19:00 (17:00 GMT).

Polling stations will remain open in some big cities until 20:00 local time (18:00 GMT), with early estimates of the result due to be reported immediately after they close.

Over 50,000 police officers have been deployed to maintain security.

France is set to elect either its first female leader, or its youngest ever president.

The poll is also unprecedented because neither candidate is from a mainstream political party.

During the first-round of voting, French voters rejected the two big political parties - the Socialists and the Republicans - that have governed for decades.

The run-off will also be keenly watched across Europe, because it comes ahead of elections in Germany and the UK, and as Britain negotiates its exit from the EU.