Sarkozy was acquitted by a Paris court of all other charges on Thursday, including passive corruption.
The court was now set to explain its findings and announce sentencing.
Sarkozy, who has always denied the charges, was accused of making a deal with Gaddafi in 2005, when he was France's interior minister, to obtain campaign financing in exchange for supporting the then-isolated Libyan government on the international stage.
The 70-year-old has been on trial since January.
Sarkozy had said the case was politically motivated.
The court found him guilty of criminal conspiracy between 2005 and 2007. The court added that after that he was president and covered by presidential immunity.
Despite lingering legal headaches, and having his Legion of Honour, France's highest distinction, stripped in June, Sarkozy remains an influential figure on the French political stage.
He recently met with his former protege, Prime Minister Sebastien Lecornu, and has also lent credibility to the National Rally, led by Marine Le Pen, saying the far-right, anti-immigrant party now forms part of the "republican arc".
Sarkozy has faced several legal battles since leaving office.
