France's youngest ever PM Fabius bows out

France's youngest ever PM Fabius bows out veteran French politician Laurent Fabius bowed out of government on Wednesday after a career spanning more than three decades that saw an early string of scandals but ended with his shepherding a complex climate deal as foreign minister.

Fabius holds the distinction of being France's youngest ever prime minister, a post he took up at 37, and has remained a Socialist heavyweight, ending his career in the ornate hallways of the Quai d'Orsay as his country's top diplomat.

Amiable and sometimes witty in person, the cerebral 69-year-old also has a reputation for being aloof.Nevertheless, his experience made him a popular foreign minister with the French people, who largely saw him as a fitting representative abroad.

Today, President Francois Hollande nominated Fabius to head France's prestigious Constitutional Court, a post the outgoing foreign minister told reporters he would take up in March "if things go as planned".

Segolene Royal, the high-profile environment minister and ex-partner of President Francois Hollande, is among the rumoured successors, but former prime minister Jean-Marc Ayrault is also believed to be in the frame.

As foreign minister since 2012, Fabius helped to negotiate the Iran nuclear deal, as well as dealing with the thorny dossiers of the Syria conflict, and the growing threat of jihadism in western Africa, where French troops are deployed.

Journalists became accustomed to his pithy expressions. Whether discussing the Islamic State group or Nigeria's Boko Haram, he would often repeat: "They are fake believers, but true criminals."

However, it is Fabius's final big project that is likely to shape his legacy: sealing a historic deal to save mankind from global warning.

As host of the global climate talks at the end of 2015, he presided over 13 days of gruelling talks to get 195 nations to agree on transforming the energy system underlying the world economy.

While fending off rumours of ill health -- and a persistent suggestion that he suffered from Parkinson's -- Fabius threw himself into the complex world of climate science and politics for two years preceding the talks.

He made 12 trips to China, four each to India and Saudi Arabia, and also went to Brazil and South Africa to get them on board and listen to their concerns.

Fabius, who comes from a long line of art merchants, is independently wealthy, and his status as the richest of the Socialist ministers has been seen as off-putting to the rank and file.

Haughty, highly pedigreed and clad in classic suits -- Hermes, according to one local report -- he has often been labelled a member of the "gauche caviar", the French term for a champagne Socialist.