The broad left-wing alliance under Jean-Luc Mélenchon and Marine Le Pen's far right were described as a pincer movement from the extremes by our Paris correspondent Hugh Schofield.
The surprise of the elections was the success of Marine Le Pen's far right National Rally, which increased its presence in the Assembly tenfold.
What changed this time was that the far right won more than half of its 108 run-offs with the Macron alliance Ensemble.
Supporters of both left and far right loathed "Macronism" so much that they stopped voting against each other, he said.
National Rally MP Laurent Jacobelli said the Assembly had changed its face and would no longer be filled with a team of pro-Macron "yes-men" ready to accept his every proposal.
Both parties aim to resist the president's programme of reforms, although National Rally has said it may back measures to alleviate the cost of living crisis if their own proposals are adopted.
The far right wants to keep it as it is, and Nupes wants to bring the pension age down to 60?
France's far right and left both make breakthroughs
France's far right and left both make breakthroughs
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