* Former leader aims to win back presidency from Hollande
* Sarkozy must first tackle party primaries in November
* Recent focus has been on security, immigration

Nicolas Sarkozy announced on Monday that he would seek to win back the French presidency in 2017 should he win November's conservative Les Republicains party primaries.
Sarkozy, 61, was unseated from the Elysee Palace at the last election in 2012 by the now deeply unpopular President Francois Hollande.
"I have decided to be a candidate for the 2017 presidential election. I felt I had the strength to lead this battle at a troubled time in our history," Sarkozy wrote on his social media pages ahead of the publication of a book called Everything for France on Wednesday.
A hyperactive and divisive figure both loved and loathed among right-wing voters, Sarkozy said in the book's extracts that he would join the conservative Les Republicains party primaries scheduled for November.
More than a dozen contenders are vying for the party ticket as candidate, including main rival, Alain Juppe.
Sarkozy had done little to conceal his desire to return to power since taking the helm of France's main right-wing party in late 2014, but two months ago trailed Juppe in opinion polls.
In July, before Islamist militants struck France twice in two weeks, he overtook Juppe among core Les Republicains supporters, though he was still less popular than Juppe among all centre-right voters.
"The five years that come will be full of danger, but also of hope," Sarkozy wrote.
The two-time former interior minister has been scathing of Hollande's security record, urging France to get tough on immigration, crack down on suspected Islamists and halt the erosion of France's secular identity.
Courting voters tempted towards France's strengthening far- right National Front party, Sarkozy has laced recent speeches with references to national identity and blames "cowardly leaders" for a loss of French culture.
His emphasis on hot-button topics of French identity and his ability to present himself as an experienced Commander-in-Chief at a time France is under emergency rule may boost his chances, foreign diplomats and political analysts say.
Even so, legal troubles surrounding party financing and overspending by his 2012 presidential campaign, as well as his outsized personality could yet trip him up.
Sarkozy credits himself with steering Europe through its worst economic and financial crisis since the Great Depression during his 2007-2012 term.
But his abrasive manner repelled many voters and his weak performance on free-market reforms to revive the economy disappointed French business leaders.
The November 20 primary is the first ever to be held by France's main right-wing party.