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 had kept investigators at arm's length while he was president by using the immunity that comes with the post.
Under French law, preliminary charges mean the investigating judge has determined that 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 for trial or drop the case.
Chirac became the 21st suspect to face preliminary charges in the probe. The investigation centers on whether Paris City Hall, under Chirac's tenure, was paying the salaries of people who in fact were not working for it.
Chirac was mayor of Paris from 1977-95. He was president of France from 1995 until May 16 this year.
The judge, Xaviere Simeoni, on Wednesday questioned Chirac about the organization of City Hall while he was in charge, according to his attorney.
Chirac will face follow-up questioning about the suspected fake jobs themselves "in a few weeks or a few months," the lawyer added.
Now back in civilian life, 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.
Respected daily Le Monde said Chirac is 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.