Paris (AFP) - French President Emmanuel Macron will on Thursday reveal his long-awaited response to almost half a year of street protests in a reform plan that could prove decisive for his presidency and long-term political future.

Macron, 41, swept to power in 2017 on hopes he would be a youthful breath of fresh air for France. But since November he saw the momentum sucked out of his presidency by the weekly "yellow vest" protests against social inequality.

On Thursday night, at 6:00 pm (1600 GMT) Macron will hold a formal press conference to announce a series of reforms drawn up after a vast listening exercise he launched in response to the protests.

He is expected to announce important, but not revolutionary reforms, including tax cuts for middle classes, as well as the abolition of the ENA administration school which has become a direct feeder for the French elite.

- 'Act 2 of presidency' -

For Macron, known to favour surprise and the dramatic gesture, the stakes are huge.

"Macron prepares to launch Act 2 of his presidency," said the Le Figaro newspaper.

Polls show his popularity rating stuck on or even under 30 percent, a far cry from the heady days after his inauguration almost two years ago when his approval rating was over 60 percent.

Macron already has his eye on 2022 presidential elections, heavily aware that his two predecessors Nicolas Sarkozy and Francois Hollande only lasted for one term and failed to implement lasting change.

At stake is not just his ambitious agenda to modernise France but his status as a global statesman able to stand up to US President Donald Trump and lead Europe as German Chancellor Angela Merkel steps aside and the UK is bedevilled by Brexit.

But even the timing and medium of Macron's big announcement has been entwined in delay and confusion.

Last Monday evening on April 15, a pre-recorded address by the president announcing the new measures was in the can and ready to be be broadcast across France.

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But just two hours before it was to go out, the devastating fire at Notre-Dame forced the presidency to cancel the broadcast and Macron rushed to the burning Paris cathedral.

- 'Tumult resumes' -

The fire was put out with much of the cathedral still intact. Macron addressed the nation on Tuesday last week, but devoted his speech from the Elysee presidential palace to the Notre-Dame fire, saying the time was not right for the "tumult" of politics to resume.

But in a major PR embarrassment for the Elysee, the entire text of the original speech leaked out to the media, although the video recording of the cancelled address has reportedly been destroyed.

In the shelved speech, Macron had vowed to lower taxes on the middle classes -- a measure he says he will pay for by cracking down on tax evasion.

He also promises a review in 2020 of his highly unpopular decision to cut a "fortune solidarity tax" on high earners.

- 'Unprecedented exercise' -

The situation created a major quandary for the Elysee, which at a stroke lost the chance of what officials call "l'effet waouh" (wow factor) and had to decide whether to rehash the old speech or try for something fresher.

"Everything can still be improved or deepened," said a presidential official, asking not to be named.

The official said some key announcements -- like cutting taxes and abolishing ENA -- would not be changed. "But for other things, there is nothing to stop it being completed or added to."

The Journal de Dimanche newspaper also said that the situation was not entirely disadvantageous.

"The delay... gave Macron the chance to watch the mixed reaction to his speech that never was and draw conclusions."

Also up in the air was how to deliver the message with the Elysee eventually plumping for a press conference in what will be a first for a head of state who critics say has kept a near imperial distance from the media.

While Macron has taken questions abroad from reporters and when foreign dignitaries come to Paris, this will be the first time he holds a full wide-ranging press conference with domestic media in France.

"This is an unprecedented exercise for Emmanuel Macron, who has been inclined to short-circuit traditional media and preferring a locked up communication carried out via social media," said the Le Parisien newspaper.