President Nicolas Sarkozy's re-election hopes were hit by more sleaze claims Thursday when a second close aide was charged with graft by judges investigating alleged kickbacks on an arms deal.

Allegations that Sarkozy allies funded a previous centre-right campaign through a Pakistani submarine contract follow claims that party members received cases of cash from African leaders and brown envelopes from an heiress.

Just seven months before he is to go to the country to seek another five year mandate, some of Sarkozy's closest allies are facing criminal investigation in a series of sensational party funding scandals.

Nicolas Bazire, a businessman and former state official who was best man at Sarkozy's wedding to supermodel Carla Bruni in February 2008, was detained on Wednesday and questioned overnight before being charged on Thursday.

Another Sarkozy ally, Thierry Gaubert, was charged on Wednesday as part of the probe into the Pakistani deal. Both men are now subject to judicial probes into "misuse of public funds" and could face trial, judicial sources said.

Prosecutors suspect middlemen paid huge kickbacks on the Pakistani contract to members of former prime minister Edouard Balladur's 1995 presidential campaign, in which then budget minister Sarkozy served as spokesman.

Bazire, 54, was Balladur's chief of staff at the prime minister's office and ran his campaign. Gaubert worked for Sarkozy when he was mayor of the Paris suburb of Neuilly and was his communications adviser as minister.

Controversy over the contract erupted last year, when investigators suggested a 2002 bomb attack in Karachi that killed 11 French engineers working on the project was a revenge attack for bribes not paid.

Balladur's presidential bid was defeated by Jacques Chirac, who, on coming to office, cancelled payments to middlemen on the contract, allegedly angering Pakistani intelligence officers who stood to profit from the deal.

Investigators and relatives of the French dead suspect Pakistanis staged the bomb attack -- officially blamed on Al-Qaeda -- in revenge. Sarkozy has dismissed claims that Balladur's campaign took kickbacks on the deal.

Nevertheless, the charges against two of his closest allies pushed the story back onto the front pages Thursday, completely overshadowing Sarkozy's speech to the United Nations General Assembly on the Middle East crisis.

Investigators are probing links between Gaubert and the Franco-Lebanese businessman Ziad Takieddine, who was charged last week with fraud over arms contracts with Pakistan and Saudi Arabia in which he was allegedly middleman.

A witness questioned by police on 8 September said Takieddine often travelled to Switzerland in the mid-1990s with Gaubert to get cases of cash that were handed over to Bazire in Paris, the news website Mediapart said.

News weekly the Nouvel Observateur identified the witness as Princess Helene of Yugoslavia, who went through a difficult divorce from Gaubert.

France's Constitutional Court was legally advised in 1995 that Balladur's campaign accounts should be rejected because of question marks over huge cash donations, but members eventually voted to approve them on a close vote.

Sarkozy came to office in 1997 vowing to lead an "irreproachable republic", but his camp has since been tainted by a series of scandals, and opinion polls show him likely to be beaten next year by a Socialist candidate.

Before the Karachi scandal caught up with his inner circle, Sarkozy found himself accused of receiving illegal campaign donations from France's richest woman, 88-year-old L'Oreal shampoo heiress Liliane Bettencourt.

Investigations into the Neuilly-based billionaire's finances have now been split into eight overlapping judicial probes, including one alleging illegal funding of figures from Sarkozy's centre-right UMP.

Sarkozy has neither been charged nor questioned himself -- and fiercely denies any personal wrongdoing -- but his then budget minister and former UMP fundraiser-in-chief Eric Woerth was forced to resign.

Meanwhile, last week, Sarkozy's camp suffered collateral damage when lawyer Robert Bourgi alleged that between 1995 and 2005 he brought Chirac and ally Dominique de Villepin 20 million dollars from African dictators.

Bourgi's claims appeared designed to damage Chirac and Villepin, Sarkozy's enemies, but the Africa middleman is now an unofficial adviser to the current president and some witnesses claim payments continued to Sarkozy's office.