What was the 'Lybian case' that has led to Nicolas Sarkozy's conviction?

Former French President Nicolas Sarkozy is starting a 5-year prison sentence after he was found guilty in the so-called 'Lybian Case'. Prosecutors said his aides, acting in Sarkozy's name, struck a deal with Kadhafi in 2005 to illegally fund his victorious presidential election bid two years later.