A French court on Thursday rejected former President Nicolas Sarkozy's appeal over charges of illegal campaign financing in 2012, maintaining an earlier decision to put him on trial, according to local report.

After losing the appeal, Sarkozy, 63, would face trial over allegation of false accounting during his election campaign that allowed him to exceed spending limits.

If convicted, the former head of state risks a one-year jail sentence.

Thirteen others, who were main figures in Sarkozy's 2012 campaign, are also to face trial for alleged "breach of trust or concealment," and "fraud and complicity" in illegal campaign financing.

In 2013, Sarkozy was accused of exceeding spending limits by nearly 23 million euros (26.23 million U.S. dollars) for his failed election campaign in 2012, 2.1 percent more than is allowed under French law.

The so-called "Bygmalion affair" began after claims that invoices for Sarkozy's campaign were passed off as party expenses.

However, the conservative politician had repeatedly denied knowing about any false accounting.