French President Emmanuel Macron's decision to call snap parliamentary elections has plunged the country into severe political uncertainty.

Two decades of relative stability -- which have largely seen president, prime minister and parliament working in harmony -- now look set to be shattered.

Polls project that none of the three main political camps -- the far-right National Rally (RN), the leftist New Popular Front (NFP) or Macron's centrists -- will win an outright majority and will struggle to form a government.

AFP looks at four possible outcomes:

- Cohabitation -

The far-right National Rally of three-time presidential candidate Marine Le Pen and current party leader Jordan Bardella are tipped to be the party with most seats after the second round on July 7.

If the RN and its allies did secure a majority in the National Assembly, Macron would find himself in a "cohabitation", in which the president and government are from opposing parties.

Post-war France has experienced three such forced marriages. All were between the left and the centre-right with the last from 1997-2002 between President Jacques Chirac and Socialist premier Lionel Jospin.

A cohabition between the Macron and his far-right arch-enemies would likely be a much unhappier affair.

While the far-right would be able to implement part of its domestic programme, on, for example, curtailing immigration, only the president can call a referendum or trigger a vote on constitutional changes.

The president, who usually sets foreign and defence policy, could also find his hands tied if the RN appointed nationalist defence and foreign ministers opposed to his worldview.

- Coalition -

France has spurned coalitions since the post-war 4th Republic (1946-1958) when the country went through 22 governments in 12 years.

Since losing his parliamentary majority in 2022, Macron has sought to cobble together alliances in parliament on a vote-by-vote basis or to force through legislation without a vote rather than form a pact with another party.

The RN or the left could try do the same if they fall short of a majority but a minority government of the far-right or left would likely fail to pass a vote of no confidence.

Aware of the risks, RN leader Bardella has said he will refuse to become prime minister unless he wins an outright majority.

Macron's camp hopes that in the event of a hung parliament it could form a coalition with moderates of the left and right.

As part of its outreach to possible allies, Macron's party has not entered candidates in 67 constituencies where centre-right or centre-left candidates are running.

But Macron has limited his options by putting the hard-left France Unbowed (LFI) -- the dominant force in the NFP -- on a par with the far-right in what he calls the country's "extremes". He accuses LFI of anti-Semitism, which it rejects.

- Caretaker government -

Another option would be for Macron to appoint a technocratic non-partisan government which all parties could get behind.

Camille Bedock, a political scientist at the Emile Durckheim centre in Bordeaux, cites the example of Italy, where respected former European Central Bank chief Mario Draghi formed a national unity government in 2021 when Italy was in turmoil. It lasted a year-and-a-half.

Bedock said Macron could also decide to leave the current government headed by his party's Gabriel Attal in place in a caretaker capacity for a year. He could then call new elections.

This would have the benefit of ensuring continuity through the Olympic Games (July 26-August 11) when the country will be under intense global scrutiny.

Whether the far-right or left would support such a move, which would effectively buy Macron time to try turn around his presidency, is highly uncertain.

- Macron resigns -

The most dramatic scenario would see Macron resign if faced with the prospect of being neutered by the far right or the hard left.

At the moment both camps are signalling that, rather than work with the president to lift France out of political paralysis, they would pressure him to step aside.

Le Pen, who is expected to try succeed Macron in 2027 presidential polls, has warned that he "will have no choice but to resign" in the event of a "political crisis".

Macron has vowed to remain on office until the end of his second term in 2027, whatever the outcome.