Paris (AFP) - With little more than a year to go before presidential elections, French opposition leader Nicolas Sarkozy has admitted to some "regrets" over his time in power in a new book to be published Monday.

Sarkozy, 60, faces an uphill struggle as he tries to see off more popular members of his party, The Republicans, in order to make a new bid for the presidency in May 2017.

His new book, "France for Life", blames his defeat at the hands of Francois Hollande in 2012 on his failure to get tough on France's famously generous benefits and heavy taxes.

"Today, I regret delaying some reforms that should have been made in the first days of my presidency," writes Sarkozy, who ran the country from 2007 to 2012.

He admonishes himself for not challenging the 35-hour working week introduced by the Socialists in the late 1990s, or the "solidarity tax on fortunes" that targets the richest citizens but is accused by right-wing opponents of driving wealthy people out of the country.

Actor Gerard Depardieu and rock star Johnny Hallyday are among those who have left France in recent years to escape its hungry taxmen.

Sarkozy also acknowledges his reputation for being short-tempered, regretting that he "gave into anger" on occasion, such as the time he was caught on camera mumbling "Get lost, you stupid bastard" at a man who insulted him during an agricultural show.

The decision to go on a yachting holiday with a millionaire friend immediately after winning the election -- a time when France was plunging into an economic crisis -- also makes it onto the list of regrets.

He now says he was trying to save his marriage, which soon ended in divorce and led to his much-publicised relationship with singer-model Carla Bruni, now his wife.

"I should have anticipated better, and been more cautious, and put my new status as president before everything," he writes.

- Return to politics -

Sarkozy makes no secret of his ambitions to return to the Elysee Palace.

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"With this book, Nicolas Sarkozy is not offering his memoirs, he is giving us a self-examination designed for an eventual return to power," the daily Le Figaro wrote on Friday.

After his defeat in 2012, Sarkozy vowed to disappear from the public eye, saying he was done with politics.

It took only two years for him to change his mind, returning to lead the UMP party -- which he renamed The Republicans -- and lining himself up for another possible run at the presidency in May 2017.

But while he remains popular with more right-wing sections of his party for his willingness to challenge some of France's tax-and-spend policies and his tough talk on immigration, he is a hate figure for more left-leaning voters.

Opinion polls are not looking favourable for him, and he faces a tough primary against his party rivals at the end of the year.

Only 21 percent of centre-right voters said they backed Sarkozy in a poll this week, way behind his main Republican rival, Bordeaux mayor Alain Juppe, on 45 percent.

Sarkozy has also been dogged by scandal since leaving office, and uses the new book to once again deny any knowledge of the "Bygmalion affair", a corruption scandal centred on claims that his party paid some of his campaign expenses to get around strict spending limits.

The scandal involving PR firm Bygmalion has dogged Sarkozy since he went into opposition and led to charges against party leader Jean-Francois Cope.

In the book, Sarkozy reiterates that he "knew nothing about this company (Bygmalion)," which is accused of orchestrating the budget fiddle.