Profile: Nicolas Sarkozy
Nicolas Sarkozy looks set to aim for the presidency again, despite corruption investigations and rivals hoping to lead the conservative UMP opposition party.
Mr Sarkozy, 59, became France's first president not to be re-elected for a second term since Valery Giscard d'Estaing in 1981.
But now the man who beat him, Socialist leader Francois Hollande, is the most unpopular French president in modern times, opinion polls suggest.
Depicting France as on the "edge of an abyss", Mr Sarkozy has said he cannot allow himself to leave his country "between the drama of the FN (far-right National Front) and the end of Socialism".
Securing the UMP leadership would give him the launch pad to challenge for the presidency in 2017.
But he is dogged by inquiries that have their roots in the funding of his successful 2007 election campaign.Tied in legal knots
An anti-corruption team in Nanterre, in the western suburbs of Paris, placed him under formal investigation on suspicion of trying to influence senior judges.
His 15-hour stay in policy custody on 1 July 2014 was unprecedented for an ex-president in France. His supporters openly accuse his political opponents of trying to sabotage his return to the political mainstream.
The allegation is that he tried to obtain details from a magistrate about legal proceedings against him in 2013, when his campaign finances came under suspicion.
The investigation could lead to a charge of influence-peddling. Mr Sarkozy is suspected of having promised a prestigious role in Monaco to a magistrate, Gilbert Azibert, in exchange for information.
Mr Sarkozy's lawyer Thierry Herzog and Mr Azibert were also placed under formal investigation.
Last year Mr Sarkozy was also charged with taking advantage of the frail, elderly L'Oreal heiress Liliane Bettencourt. She was allegedly persuaded to donate big sums to the UMP. The case against him was later dropped.
Another inquiry concerns allegations that Mr Sarkozy received campaign funding from the late Libyan strongman Col Muammar Gaddafi.
And a case called Bygmalion could yet damage Mr Sarkozy's chances of a comeback. The UMP is suspected of having fraudulently covered up illegal campaign funding in 2012.
UMP leadership primaries are scheduled for 2016 and Mr Sarkozy is likely to face tough rivals - former Prime Minister Francois Fillon and his own former Foreign Minister Alain Juppe.Celebrity lifestyle
Mr Sarkozy kept a low profile after his defeat by Mr Hollande in the 2012 election.
He appeared to rule out any return to frontline politics, devoting himself instead to family life and lucrative appearances on the international conference circuit.
Critics nicknamed his presidency "bling-bling", seeing his leadership style as too brash, celebrity-driven and hyperactive for a role steeped in tradition and grandeur.
That celebrity image was reinforced by his marriage to supermodel and singer Carla Bruni in 2008. The couple had a daughter, Giulia, a few months before the 2012 election.
Mr Sarkozy, who is twice divorced, also has a son from his second marriage and two sons from his first marriage.Tough on immigration
A veteran conservative politician, Mr Sarkozy angered human rights activists with his stance on immigration.
As interior minister he notoriously talked of hosing down troubled housing estates, describing young delinquents in the Paris suburbs as racaille, or rabble.
That blunt comment - made before the 2005 riots - encouraged some critics to put him in the same category as the then far-right leader Jean-Marie Le Pen.
Later as president he pushed through measures to curb illegal immigration - including highly controversial mass deportations of Roma (Gypsies).
At the same time, he advocated positive discrimination to help reduce youth unemployment - a challenge to those wedded to the French idea of equality.
Towards the end of his presidency, unemployment claims surged to their highest level in 12 years.
Yet he had been at the forefront of the European response to the global economic crisis in 2008 and helped establish the G20 summits involving the world's biggest economies.
He also saw through unpopular, but arguably necessary, reforms: raising the retirement age from 60 to 62, relaxing the 35-hour working week, overhauling the universities and altering the tax system to encourage overtime and home ownership.Political fighter
On the international stage, Mr Sarkozy was often described as an Atlanticist, though he opposed the war in Iraq.
In March 2011, France was first to send warplanes into action against Muammar Gaddafi's forces in Libya, spearheading the foreign intervention that enabled the Libyan rebels to succeed.
He was credited with brokering an end to the August 2008 conflict between Russia and Georgia, and his performance while holding the six-month EU rotating presidency is remembered as assertive.
In response to the global financial crisis of 2008, he vowed to punish speculators and advocated a strong state role in the economy.
Leading the European Union response, he developed a close working relationship with Chancellor Angela Merkel of Germany.Immigrant roots
Unlike most of the French ruling class, Mr Sarkozy did not go to the Ecole Nationale d'Administration, but trained as a lawyer.
The son of a Hungarian immigrant and a French mother of Greek-Jewish origin, he was baptised a Roman Catholic and grew up in Paris.
He began his political career as mayor of the affluent Paris suburb of Neuilly from 1983 to 2002.
National attention came in 1993, when he personally intervened to free infants held hostage by a deranged man in a kindergarten, who was later killed by police commandos.
Initially a protege of Jacques Chirac, he became the right-hand man of Prime Minister Edouard Balladur in 1993-95, serving as budget minister.
When he backed Mr Balladur for the presidency in 1995, the decision caused a lasting rift with Mr Chirac, the successful candidate.
Mr Chirac famously chided him in his memoirs for being "irritable, rash, overconfident and allowing for no doubt, least of all regarding himself".