President Emmanuel Macron's bloc has come out on top in most of the constituencies of French voters overseas who went to the polls ahead of the rest of France, but with a stronger challenge from the left compared to 2017.

Eleven seats out of 577 in parliament are reserved for geographical zones where French citizens live abroad, such as one for those in Canada and the United States and another for Central and Eastern Europe.

Macron's "Ensemble" alliance won the largest number of votes this weekend in eight of them, while the left-wing coalition NUPES led by leftist Jean-Luc Melenchon, was ahead in two.

Nine out of the 11 constituencies that voted will see a second round run-off between Ensemble and NUPES, an improved performance for the left from 2017, when it qualified for the second round in five constituencies, thanks to an unprecedented alliance formed between left-wing parties to challenge the presidential majority this year.

Those votes will take place on June 18-19.

Voters in France will cast their ballots in two rounds on June 12 and 19. An IFOP poll showed for the first time last week that Ensemble may fall short of an absolute majority in parliament, potentially complicating Macron's agenda.

The only candidate backed by Macron who did not make it through to the second round was Manuel Valls, a former Socialist prime minister under Francois Hollande, who ran in the Iberian peninsula constituency, covering Spain, Portugal, Andorra and Monaco.

Macron backed Valls at the expense of his 2017 candidate, Stéphane Vojetta, who went onto run a dissident campaign against Valls and won to face the left-wing candidate in the run-off.

"An election is a moment of truth," Valls tweeted in acceptance of defeat before deleting his Twitter account.

An absolute majority requires a minimum of 289 seats in parliament.

The IFOP poll showed Ensemble winning 270-310 seats in the second round, and gave NUPES 170-205 seats. On the right, Les Republicains were forecast in the same poll to get 35-55 seats and the far-right Rassemblement Nationale was projected to win 20-50.

Melenchon, who is running on a hard-left ticket with proposals to lower the retirement age, raise the minimum wage and offer more social and environmental protections, casts Macron as a liberal who will further unwind workers' rights and serve the interests of the rich. If Macron wins the legislature after his re-election in April, he has said his government's priorities will include action to combat climate change and raising the retirement age. (Reporting by Layli Foroudi; Editing by Alison Williams)