All the main candidates are now on the starting line for France's April presidential election, after Emmanuel Macron confirmed on Thursday that he was running for a second term.

* WHO WILL WIN?

Macron is the favourite in opinion polls. But the projected margin is narrower than when he was elected in 2017 and he is facing stiff competition from the right.

Even if he succeeds, Macron will need his centrist La Republique en Marche (LaRem) party - which has failed in all recent local elections - and its allies to win a parliamentary election in June if he is to have a strong platform to implement his policies.

* WHAT TO WATCH FOR:

- The race between Valerie Pecresse of the conservative Les Republicains and the far-right's Marine Le Pen and Eric Zemmour to be Macron's challenger in the likely second-round run-off.

- Will Macron trip up and lose his lead? In 2017, the early favourites lost the election to then-outsider Macron.

- Voter uncertainty. Opinion polls show many are unsure who they will vote for, and turnout could be lower than usual, adding more uncertainty.

* WHAT WILL THE ELECTION BE FOUGHT OVER?

- The election campaign starts amid a war in Ukraine. Polls show that could impact the vote's outcome, with initial surveys indicating a boost for Macron.

- Immigration and security issues had long been at the forefront of the political debate, but opinion polls show purchasing power as one of voters' top concerns.

- Economic recovery, and whether it holds. Opinion polls show voters are unhappy with Macron's economic policy, but unemployment is at its lowest in years and those surveyed don't think any of his opponents would do better.

* WHY DOES IT MATTER?

- Russia's invasion of Ukraine has sent shockwaves through Europe and beyond. The winner of France's election will have to deal with the fallout.

- Now that Britain has left the European Union, France is the bloc's main military power. It's also the undisputed second biggest economy in the EU, and Angela Merkel's exit as German chancellor has given Macron a more prominent role in Europe.

- The next president will face soaring public deficits to tackle the impact of the pandemic, a pension system many say needs reforming, and moves to re-industrialise France.

* KEY DATES

April 10 - Presidential election first round

April 24 - Second round held between the top two candidates if none wins a simple majority of votes cast in the first round.

May 13 - The latest day the new president takes office.

June 12 and 19 - Parliamentary election.