The former close aide to Sarkozy is likely to face judicial action in relation to the matter.
Guéant received the money between 2002 and 2004 when he ran the office of then interior minister, Nicolas Sarkozy. Guéant himself became interior minister in 2011.
Guéant's associates maintain the money he received was not used for his own personal enrichment but used instead to pay special bonuses to the police officers assigned to ensure Nicolas Sarkozy's personal protection.
When the existence of the money first came to light, during a probe into separate allegations that Sarkozy's successful 2007 presidential campaign was partly funded by Moamer Kadhafi, Guéant described it as bonus money.
The longstanding system of paying significant cash bonuses to police officers was abolished during the tenure of socialist prime minister Lionel Jospin (1997 to 2002) but appears to have been re instated in 2002 when Sarkozy became Interior Minister.
Today's (socialist) Interior Minister, Manuel Valls, declared that there will be strict new rules over the money dedicated to police work on investigations.
Several politicians on the left are now suggesting Nicolas Sarkozy must have been aware of the monthly payments to Guéant.