Almost two months after France's inconclusive legislative elections, impatience is growing with the reluctance of President Emmanuel Macron to name a new prime minister in an unprecedented standoff with opposition parties.

Never in the history of the Fifth Republic -- which began with constitutional reform in 1958 -- has France gone so long without a permanent government, leaving the previous administration led by Prime Minister Gabriel Attal in place as caretakers.

A left-wing coalition emerged from the election as the biggest political force but with nowhere near enough seats for an overall majority, while Macron's centrist faction and the far-right make up the two other major groups in the National Assembly.

To the fury of the New Popular Front (NFP) coalition, Macron earlier this week rejected their choice of economist and civil servant Lucie Castets, 37, to become premier, arguing a left-wing government would be a "threat to institutional stability".

Macron insisted during a Thursday visit to Serbia that he was making "every effort" to "achieve the best solution for the country". 

"I will speak to the French people in due time and within the right framework," he said.