The ban was the latest twist in a bitter row over "écriture inclusive," which splits up words using a punctuation point called a middot, so that for example the plural word "amis" (friends) becomes "ami·e·s" and "citoyens" (citizens) becomes "citoyen·ne·s."
The new spellings include feminine forms rather than following the rule that plural masculine endings denote both women and men - a practice that the French ministry for gender equality has described as a form of sexual tyranny.
But the initiative has sparked fury among linguistic purists, with the Académie Française, the gatekeeper of the French language, arguing that it poses a "mortal danger" to the purity of French.
The Prime Minister has now come down on the side of the purists, banning "inclusive writing" from official publications.
Mr Philippe wrote in a memo to his ministers that "the masculine (form) is a neutral form which should be used for terms liable to apply to women".
"State administrations must comply with grammatical and syntactic rules, especially for reasons of intelligibility and clarity," he wrote.
The debate, which comes as a flurry of revelations about sexual harassment and assault continue to make headlines across the world, is however likely to rumble on.
It began when it emerged that a French publishing house had produced a primary school textbook using "écriture inclusive."
Previously some government ministries and universities had been using the gender neutral forms but that had largely escaped public attention.
It was the school textbook that infuriated the "immortels," as the Académie Française's 40 members - who include only a handful of women - are known.
They said that the move "leads to a fragmented language, disparate in its expression, creating confusion that borders on being unreadable.
"Faced with this 'inclusive' aberration, the French language is in mortal danger, for which our nation is accountable to future generations," wrote the academy's members, who would become "immortel·le·s" if described by users of "écriture inclusive."
Comment: An unusual moment of clarity there from the French government that has, in the past, furiously promoted all things post-modern.