Nicolas Sarkozy attending a meeting ahead of the 2017 presidential election | Martin Bureau/AFP via Getty Images Sarkozy recordings reveal National Front flirtation ‘Of course we have common values with the National Front,’ ex-president was recorded as saying.

PARIS — A former campaign adviser to Nicolas Sarkozy who secretly recorded hundreds of hours of conversations with the ex-president said he frequently voiced sympathy for the values of France's far-right National Front, according to excerpts from a new book.

Patrick Buisson, who advised Sarkozy during his 2007 and 2012 election campaigns, split with the conservative leader after it was revealed that for years he had carried a recording device during private conversations and meetings.

In a book that Buisson, a former journalist for far-right magazine Minute, has written based on the recordings, and which is due to be published Thursday, he cites Sarkozy as frequently reaching out to the National Front (FN).

"The values of the National Front are those of all French people," Buisson cites Sarkozy as having said in 2005, before he was president, according to excerpts from the book, "The People's Cause: Forbidden History of the Sarkozy Presidency," published Tuesday by l'Express magazine. "It's the way the FN expresses them that is shocking. The French don't like dishes that are too spicy."

In 2012, Sarkozy is quoted as firing back against criticism of the National Front by his former prime minister, François Fillon.

"What is Fillon talking about?" Sarkozy is quoted as having said. "Of course we have common values with the National Front."

In another instance, Sarkozy is quoted as reaching out to Jean-Marie Le Pen, who at the time was head of the National Front, for a nod of support between two rounds of the 2007 presidential election, which he won.

'Our ancestors the Gauls'

The publication of Buisson's book could be troublesome for Sarkozy.

Competing in a conservative party primary to win the nomination to run for re-election next year, Sarkozy faces criticism from rivals over his alleged embrace of hard-right positions. His main competitor for the Républicains party pick, former prime minister Alain Juppé, complained publicly last week about the "dismal" level of political debate in his camp, after Sarkozy argued that all French people should consider "the Gauls" as their ancestors, though Juppé did not cite Sarkozy by name.

Sarkozy's reference was charged. Most people listening to his speech would have been aware that the phrase he used — "our ancestors, the Gauls" — refers to a line from French history books distributed to schoolchildren in African colonies, and later criticized as culturally insensitive.

If Buisson's book reveals more evidence that Sarkozy flirted with the far-right, Juppé could use it as ammunition in a series of primary debates set for November — the first-ever for the French Right.

Sarkozy has trailed far behind Juppé in opinion polls for months. But a survey published by Ipsos-Sopra Steria Monday showed the former conservative chief gaining ground on his rivals, with 33 percent support among center-right voters versus 37 percent for Juppé.