The case, which has become known as the "Karachi affair", dates back to 1995 when Sarkozy was budget minister and campaign manager for former prime minister Edouard Balladur's unsuccessful bid to become president.
Balladur himself and former defence minister François Léotard are the prime targets of the legal case.
Sarkozy will be summoned by the Cour de Justice de la Republique (CJR), which deals with ministerial misconduct cases, as an "assisted witness", a status that means that he could be charged.
Investigators claim Sarkozy was part of a web of corruption behind the sale of submarines to Pakistan and warships to Saudi Arabia, back in 1994, when he was France's budget minister.
Kickbacks from the awarding of contracts are alleged to have funded Balladur's campaign.
There is also suspicion that a secret fund run by the prime minister's office was used fraudulently.
Investigators are also looking into a 2002 bombing in Karachi that killed 15 people, 11 of them French engineers, and could have been an act of revenge for a failure to pay bribes secretly promised to Pakistani officials.
This is one of a number of cases involving Sarkozy, who was questioned last year on accusations of illegal campaign funding for his 2007 presidential bid.
The former president lost his immunity when he left office in 2012.
He has not ruled out running in 2017's presidential poll and has denied any wrongdoing, as has Balladur.