Former French president Nicolas Sarkozy told his trial on charges of illegal financing of his failed 2012 re-election campaign that he had committed no wrongdoing.

A defiant Sarkozy said in court on Monday he had not been involved in the logistics of his campaign for a second term as president nor in how money was spent during the election run-up.

-Did I intend to commit a fraud, to do wrong? Was I careless? Negligent? My answer is the most formal no to all that- Sarkozy told the court. -From the moment I was told things were in order, I had no reason to give it more thought.-

Sarkozy, 66, told the judges that he was responsible for the political direction of his campaign but not the organisation of rallies, production of campaign materials and payment of bills.

Prosecutors allege that Sarkozy's conservative party splurged nearly double the 22.5 million euros ($27.28 million) allowed under electoral law on extravagant campaign rallies, and then hired a friendly public relations agency to hide the cost.

In their indictment, the prosecutors acknowledged their investigation had failed to prove Sarkozy either organised or was involved in the scheme, but argued that he benefited from it and must have been aware of it.