French President François Hollande is expected to set in motion a government reshuffle aimed at boosting his appeal to voters ahead of a bid for a second term in 2017.
Veteran foreign minister and former premier Laurent Fabius confirmed he was stepping aside as Hollande seeks fresh political momentum with just 15 months left in office.
Fabius, whose departure has long been rumoured, replied "yes" when journalists asked if he was taking part in his final cabinet meeting on Wednesday.
Fabius was widely praised for his role in sealing the COP21 climate deal, but he leaves the cabinet just as he faces an awkward time.
According to judicial sources Thomas Fabius, his son, has been charged with forgery in connection with his passion for gambling.
He was also named as a "temoin assiste" - an intermediary status between that of a witness and someone who has been charged - in connection with fraud, tax laundering, breach of trust and misuse of corporate assets, with the information confirmed by a source close to the case.
The 34-year-old son of France's top diplomat has run into a raft of legal problems over his passion for gambling, with an investigation into his financial affairs opened in late 2011 following a complaint by French bank Societe Generale.
Hollande's popularity rose after he took a tough approach on security following the November 13th jihadist attacks on Paris which killed 130 people.
But three months later, the problem that has plagued him since he came to power in 2012 - France's stubbornly high unemployment - has dragged him back down to popularity ratings of around 19 percent.
Hollande is haunted by the pledge that he made at the start of his mandate that he would not run again if he did not improve the jobless rate.
Now he finds himself under fire, not only from the opposition right-wing Republicans of his predecessor Nicolas Sarkozy, but increasingly from within the ranks of his own Socialist Party.
The right accuses Hollande of stealing its clothes, partly with his moves to increase powers for the security services following the attacks, and partly with his attempts to liberalise the economy through the government's rising star, 38-year-old Economy Minister Emmanuel Macron.
Fabius quits the stage
Fabius, 69, exits the cabinet to chair the Constitutional Court, which rules on the constitutionality of laws.
Reports say Hollande - never an ally of his - will announce the move officially on Wednesday.
"You can see it in the way he is acting and his staff are already packing up their things," one source close to Fabius said on Tuesday.
Segolene Royal, Hollande's former partner and mother of their four children, has been tipped to leave her role as environment minister and take over the foreign brief.
Royal, a failed presidential candidate in 2007, remains a largely popular figure to Socialist Party supporters.
Her departure could allow Hollande to bring a member of the Greens back into his cabinet, a move which would also allow him to extend his appeal to green-minded voters.
But Hollande has to play a careful game because his right-leaning prime minister, Manuel Valls, is hated by many ecologists.
Moving Royal to the foreign ministry would also restore the gender balance in the cabinet that was disturbed when Christiane Taubira quit last week as justice minister over her opposition to the government's moves to strip French nationality from bi-nationals convicted of terrorist offences.
Other names in the frame are former prime minister Jean-Marc Ayrault and, perhaps more surprisingly, Matthias Fekl, the 38-year-old foreign trade minister.
Fabius will quit the splendour of the foreign ministry at the Quai d'Orsay on the back of the success of the UN climate talks hosted by France in December, in which he was acclaimed for his role in holding the process together.
Fabius, who has given short shrift to rumours that his health is failing, still holds the distinction of having been the youngest prime minister in French history, having taken the post aged 37 in 1984.