"I have decided to be a candidate in the 2017 presidential election," he wrote in a new book, "Tout pour la France"
Former French president Nicolas Sarkozy launched a bid Monday to win back the presidency, announcing he would seek his party's nomination to run in next year's election.
Sarkozy, who in 2012 ended a five-year term mired in unpopularity, had made no secret of his ambition to reconquer the top office.
"I have decided to be a candidate in the 2017 presidential election," Sarkozy wrote in a new book, "Tout pour la France" (All for France), due out this week.
"France demands that you give her your all. I feel I have the strength to lead the fight at such a turbulent moment in our history," he wrote in an extract seen by AFP, alluding to the terror attacks that have rocked the country since January 2015.
The pugnacious 61-year-old conservative said, "The next five years will be filled with danger but also with hope."
Sarkozy's aides told AFP he would step down on Monday as the leader of the centre-right Republicans to focus on his bid.
Laurent Wauquiez, from the party's right wing, is expected to take the helm.
Party primaries take place on November 20 and 27. Sarkozy's first campaign stop will be on Thursday at Chateaurenard, near the southern French city of Avignon.
Sarkozy itemised major challenges in the years ahead, including strengthening respect for "French identity," restoring lost competitiveness and enforcing state authority.
On the economic front, he vowed to reduce payroll charges, scale back unemployment payments for those who are jobless for more than one year and slash income tax by 10 percent.
On immigration, he proposed "suspending" the right of family members to join a migrating relative in France. "The big problem with our immigration policy is firstly that of numbers," he said.
France's #Sarkozy announces he'll run for presidency again. Will it change anything? Vote + RT. Reply your thoughts.— Shuja Rabbani (@ShujaRabbani) August 22, 2016
His announcement coincides with a resurgent debate on the place of Islam in French society, encapsulated in the row over the "burkini" swimsuit.
Sarkozy said France's "principal battle" was over how "to defend our lifestyle without being tempted to cut ourselves off from the rest of the world".
The opposition leader, who has repeatedly dismissed Socialist President Francois Hollande as weak, said he would also restore authority in neighbourhoods where he said "minorities are successfully blackmailing the current authorities".
The politician was defeated in his bid for re-election in 2012 after conducting a campaign seen by many in his own camp as too rightwing.
Sarkozy becomes the 13th person to put their name forward for the French presidency, a job that has sweeping powers.He faces several challengers within conservative ranks.
His chief rival, former premier and Bordeaux mayor Alain Juppe, who is seen as a moderate, is the favourite to win the party's nod.
But Juppe's lead in opinion polls has shrunk in recent weeks as Sarkozy steps up his rhetoric on extremists and immigration following the July 14 truck massacre in Nice.
Sarkozy has already won the support of a Republicans heavyweight in the shape of Christian Estrosi, president of the southern region that includes Marseille.
"He is the best candidate," Estrosi told the Journal de Dimanche on Sunday.
If Sarkozy wins, he could face a rematch against Hollande, who has said he too has the "desire" for a second term.
But opinion polls overwhelmingly show the French wanting neither man as their leader. Hollande has even surpassed Sarkozy to become the most unpopular president in post-war France.
Sarkozy would also face far-right National Front leader Marine Le Pen, who is tipped to make it to a second round of voting.
The man known as "President Bling-Bling" for his flashy lifestyle and cosy ties with tycoons while in office, never digested his 2012 defeat by Hollande, whom he had written off as "useless".
After telling the French before his defeat they would never hear from him if vanquished, Sarkozy made a comeback to frontline politics in 2014.
His reputation remains tainted by two major inquiries, into alleged influence peddling and into suspected illegal funding of his 2012 election campaign.
But, true to his famous self-belief, these scandals have failed to dent his ambition of returning to the Elysee Palace.
Hollande, on a trip to southern Italy for talks with German Chancellor Angela Merkel and Italian Prime Minister Matteo Renzi, declined to comment on Sarkozy's bid, or on another challenge for the presidency launched by leftwing Socialist Arnaud Montebourg.