Former French President Nicolas Sarkozy is in the centre of an investigation of a funding probe.

Legal preceedings are being brought against Sarkozy, 61, in relation to massive over-spending during his campaign's 2012 run, which ultimately ended in an unsuccessful result.

Sarkozy had been in talks of running again for the Presidency in the 2017 elections, but accusations that his 2012 campaign costs were more than twice the legal limit may dampen those hopes.

He was questioned all day today by French magistrates, before being informed he was under official investigation.

Sarkozy claims he was not involved in the details of his campaign's finances, and has denied knowledge of the overspending.

In France, the campaign finance ceiling in 2012 stood at €22.5m, while Sarkozy is accused of overspending of spending in excess of €39m.