A judge filed preliminary charges against former French president Jacques Chirac on Wednesday in a probe of suspicions that people were given fake jobs while he was mayor of Paris, his lawyer said.

The judge placed Chirac under formal investigation for suspected embezzlement or misuse of public funds, the attorney, Jean Veil, said after the investigating magistrate questioned Chirac for nearly four hours.

The case is one of several hanging over Chirac, who managed to keep investigators at arm's length while he was president by using the immunity that comes with the post.

Chirac, 74, stepped down as president in May after holding France's top job since 1995. He was mayor of Paris from 1977 until 1995.

Under French law, preliminary charges mean the investigating judge has determined there is strong evidence to suggest involvement in a crime.

It gives the investigator time to pursue the probe before deciding whether to send the suspects to trial or drop the case.

Chirac is the 21st suspect to face preliminary charges in the probe. The investigation centres on whether Paris city hall, under Chirac's tenure, was paying the salaries of people who, in fact, were not working for it.

Chirac denied any wrongdoing in an article published Wednesday in the newspaper Le Monde.

"Never were Paris municipal resources devoted to ambitions other than acting for the Parisians. There was never personal enrichment. There was never a 'system,"' Chirac wrote.

The probe is focusing on about 20 contested contracts, some of them short-term, spread over an 18-year period, he added.

The judge, Xaviere Simeoni, questioned Chirac on Wednesday about the organization of city hall while he was in charge, according to Chirac's lawyer.

Chirac will face followup questioning "in a few weeks or a few months," the lawyer added.

No longer shielded by presidential immunity, Chirac is seeing several cases come back to trouble him.

In July, he was questioned as a potential suspect by another judge, Alain Philibeaux, in a political financing probe. Philibeaux had been waiting for years to talk to Chirac about how much he knew.

Le Monde said Chirac is specifically suspected of having hired a chauffeur in 1990 who later told investigators that he in fact worked for a senator from Chirac's political party at that time.