France’s ex-President Nicolas Sarkozy should stand trial for breaching campaign spending limits, the French prosecutor’s office has recommended.

The announcement follows a long investigation into claims that Nicolas Sarkozy’s then-UMP party falsified accounts in order to hide 18 million euros ($20 million) of spending in 2012.

Nicolas Sarkozy lost the 2012 race to Francois Hollande, but is hoping to run again in 2017 election.

The former president said he left it to subordinates to raise campaign funds.

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The advice from the prosecutor’s office in Paris is not definitive – an investigating magistrate will now make a final decision over whether Nicolas Sarkozy should stand trial.

The prosecutor says that, as the candidate, Nicolas Sarkozy was ultimately responsible for his own campaign – and in any case there is also considerable evidence he was warned at the time of the risks of over-spending.

To become nominee for The Republicans, the party he renamed from the UMP, Nicolas Sarkozy will have to defeat ex-prime minister and mayor of Bordeaux Alain Juppe, whom he trails in opinion polls.

The affair is known as the Bygmalion scandal. It centers on claims that Nicolas Sarkozy’s party, then known as the UMP, connived with a friendly PR company to hide the true cost of his 2012 presidential election campaign.

France sets limits on campaign spending, and it is alleged Bygmalion invoiced Nicolas Sarkozy’s party rather than the campaign, allowing the UMP to exceed the limit.

Bygmalion employees have admitted knowledge of the ruse and several UMP members already face charges.

However, Nicolas Sarkozy has repeatedly denied that he was aware of the overspending.