A French MP has tabled a bill to punish discrimination against regional accents – dubbed “glottophobia” - after one of the country’s highest-profile politicians mocked a journalist's southern intonation.

The proposal came a day after Jean-Luc Mélenchon, leader of the far-left France Insoumise (France Unbowed) movement and a former presidential candidate, was caught on camera rudely haranguing a journalist with a southern accent who asked him a question outside parliament.

French police on Tuesday raided the Leftist’s party headquarters after prosecutors opened an inquiry into suspected campaign financing violations and "fake jobs" for EU parliament assistants. He was quizzed for five hours on Thursday over the probes.

Asked for a comment from a journalist from the southwestern city of Toulouse, where silent vowels are more “sung” than further North, a clearly irked Mr Mélenchon hit back mockingly: "Qu'esseuh-que ça veut direuh ?" (the French equivalent of saying:" Whatadoesa thata mean?).

"Can someone ask me a question in French? And (make it) a bit more understandable...," the fiery revolutionary asked reporters in the video clip, widely circulated on social media.

It prompted an angry response from Parisian MP Laetitia Avia.

"Do we speak French any the less with an accent. Must one suffer humiliation if one doesn't speak standard French? Because our accents are our identity, I am tabling a bill to recognise glottophobia as a source of discrimination," Ms Avia tweeted.