PARIS - The Paris appeals court ruled Thursday that investigating judges didn't break any laws when they tapped conversations between former President Nicolas Sarkozy and his lawyer in connection with a probe into past campaign financing.

The decision Thursday is a new blow to the conservative opposition leader as he eyes a 2017 presidential bid, because it allows investigations to resume.

Sarkozy is under preliminary charges for active corruption and influence-peddling based on information gleaned from the phone taps. It's among several legal cases he has faced since losing the presidency to Francois Hollande in 2012 - but it's the case that has the greatest chances of seeing Sarkozy sent to trial.

Sarkozy and his lawyer Thierry Herzog had protested the phone taps, saying they breached lawyer-client privilege and that the investigating judges didn't get proper authorization.

But the appeals court ruled in favour of investigators, according to Herzog's lawyer, Paul-Albert Iweins. The court found that wiretapping on different phone lines used by Sarkozy under his own name and under the false identity of “Paul Bismuth” had been legally carried out, except for one minor phone line.

Lawyers for Sarkozy and Herzog said they would appeal to France's top court, the Cour de Cassation.

Investigators tapped the phones in 2013-2014 as part of a probe into illegal financing of Sarkozy's 2007 presidential campaign. By chance, they discovered an alleged influence-peddling plot by Sarkozy and Herzog as they tried to obtain confidential information about the financing probe.

That prompted a new investigation. The ruling Thursday means that investigation can now resume after a seven-month suspension.

While Sarkozy managed recently to be cleared in some investigations, he is still dealing with a few judicial cases in which his name is mentioned.