"It's an ignominious act, not (just) a lie", Sarkozy said during a live television interview on French station TF1.
Sarkozy arrived just before 8am (0700 GMT) at the bureau of officers specialising in corruption, money laundering and tax evasion in the western Paris suburb of Nanterre, an AFP journalist said.
Le Figaro newspaper published a lengthy account of what it said was a verbatim declaration by Sarkozy to magistrates.
Nicolas Sarkozy has denounced allegations that he accepted election campaign funds from Colonel Muammar Gaddafi as "mud-slinging, calumnies and inanities".
Sarkozy, 63, was released Wednesday night but placed under "judicial control".
The case is connected to accusations that Sarkozy received money from Gaddafi to fund his successful election bid in 2007, allegations he denies and has dismissed as "grotesque".
In July 2014 Sarkozy became the first former French president to be taken into police custody over a separate inquiry into claims that he tried to interfere in another of the myriad investigations that have dogged him since leaving office.
A lawyer for the former president did not respond to a message from the AP seeking comment. Details of the conditions he has been ordered to follow have not been revealed.
Sarkozy has also sued the investigative website Mediapart for publishing a document allegedly signed by Libya's intelligence chief showing that Gaddafi agreed to give the former president up to 50 million euros ($62 million).
One of the party's lawmakers in northern France, Sebastien Huyghe, told BFM television he believed Sarkozy was the victim of "vengeance" by ex-Libyan regime members and by the French judiciary, with which he had a fraught relationship as president.
But in 2011, France and Britain took a lead role in a NATO-led campaign that helped rebels topple Gadhafi and, in October that year, kill the man who had ruled Libya, often brutally, since 1969. He is challenging an order to stand trial on charges of illicit spending overruns during his failed 2012 campaign.
"I've been living the hell of this slander since March 11, 2011" when Gaddafi first made the allegations, he added.
Anti-corruption investigators are exploring claims that a middle man transferred funds from the Libyan regime in Tripoli to Sarkozy's campaign team in Paris in suitcases stuffed with cash during the 2007 election battle.
The charges in that case were dropped in 2013.
He claimed he personally handed a suitcase containing $2.5 million (2 million euros ) in cash to Sarkozy at the then-candidate's apartment and another suitcase with $1.9 million (1.5 million euros) to Sarkozy and a close aide at the French Interior Ministry.
Brice Hortefeux, a Sarkozy ally who was a top minister during his presidency, was also questioned Tuesday.
Andy Murray looks to sport management role for future talent
He says that he still wishes to compete in professional tennis but he also wants to expand his prospects and share his knowledge. At the moment he is juggling many balls and he wants to remain focused on what he knows, but over time his company will develop.