Flessel did not elaborate further on the reasons for her departure in her statement, which thanked Macron and Prime Minister Edouard Philippe for their “constant support”.

But, according to a source, her decision to leave was “linked to her fiscal situation”.

French investigative website Mediapart reported that tax inspectors were looking into whether Flessel under-reported the earnings of the company she and her husband set up to manage her image rights.

“She did not make any mistake, that is not why she is leaving,” a source close to the former minister said, denying the allegations, which if confirmed could be embarrassing for Macron.

Prime Minister Edouard Philippe would not comment, telling broadcaster TF1 simply that Flessel “has decided not to stay in the government for reasons she described as personal,” adding it was not for him to elaborate on such reasons.

The 40-year-old reformer Macron came to power promising to clean up politics and revive France’s sputtering economy.

But over a year into his term polls show the French starting to sour on the energetic centrist, whose approval ratings fell to 31 per cent in September according to an Ifop poll – the lowest level since he took office in May 2017.

On Tuesday he attempted to rebound with two changes to his team.

Parliament speaker Francois de Rugy, a former Greens party member and Macron loyalist, took over from Hulot, an environmental campaigner who accused the president of not moving fast enough on key green pledges.

The resignation of the immensely popular Hulot was a blow for Macron, who had famously responded to US President Donald Trump’s withdrawal from the 2015 Paris climate deal with a pledge to “make our planet great again”.

It also robbed Macron of one of the high-profile political greenhorns that he brought into government last year as a sign of “renewal” in high office.

Commenting on the choice of Rugy to replace him, Stephane Rozes, professor at Sciences Po university and president of CAP consultancy said Macron had made a “safe” choice.

“Maybe he drew the conclusion that he was better off having a politician who can accept the idea of political compromise,” he said.

Philippe, however, insisted Rugy possessed “ecological conviction”.

Flessel, a popular figure who was overseeing preparations for the 2024 Olympics in Paris, announced her resignation just hours before the planned reshuffle.

Swimming champion Roxana Maracineanu, a silver medallist in backstroke at the 2000 Sydney Olympics, takes over her portfolio.

The reshuffle is the first act in Macron’s campaign to get back on track after a chequered summer.

In the biggest dent to date to his credibility one of his top security aides was caught on film roughing up protesters during a Paris demonstration.

Critics accused the president and his team of trying to cover up the incident, reinforcing Macron’s image as an aloof leader dismissive of traditional checks and balances.

“The government has been on the defensive since the summer,” said Ifop analyst Jerome Fourquet.

“It’s like riding a bike – when you stop pedalling, you fall over.”

Threatening further headaches for Macron is a planned tax payment reform.

After days of dithering the government confirmed Tuesday it will proceed with implementing a new system to deduct income tax at source.

The French currently are responsible for declaring, and paying, their own taxes.

“Income tax will be levied at source from January 1, 2019,” Philippe told TF1, saluting what he termed a simplification of the system and a “good reform” which would notably see someone retiring take a smaller tax hit at the moment they exited the workforce.

The change, which will bring France in line with most European countries, has been in the works for years but Macron had appeared this week to be having second thoughts, despite polls showing voter backing.

Analysts say that the former investment banker may be loath to be seen as responsible for a drop in workers’ net salaries on their payslips – even if the amount of tax they pay remains unchanged.