The investigation stalled after Mr Schuller went awol
Didier Schuller, who has been the subject of an international arrest warrant for "trafficking influence" and "misuse of social goods" since 1995, is expected to arrive in France by Wednesday at the latest.
His testimony could prove embarrassing for President Jacques Chirac as he gears up for a re-election battle in April.
Mr Schuller, currently in the Dominican Republic, is believed to hold key information about a bribery scandal within the Gaullist RPR party during Jacques Chirac's tenure as Mayor of Paris.
He said he would return to France after his son revealed his whereabouts last month.
'Conceived on high'
Mr Schuller will face questioning about an alleged cash for contracts racket within the public housing office in Hauts-de-Seine, which is believed to have contributed illicit funds to Mr Chirac's RPR.
Mr Schuller was director-general of the office from 1986-1994, as well as being an elected RPR representative in local politics. The office is believed to have assigned work to contractors in return for kickbacks.
A close aide to Mr Schuller was caught red-handed accepting money from a businessman in 1995, but Mr Schuller's disappearance meant that investigators made little further progress on the case.
With Mr Schuller's return, however, a new set of revelations is expected to explode onto the scene.
He has told Le Monde newspaper, that the bribery system was set up by people above him, and insinuated that Mr Chirac may have been involved.
Mr Chirac has so far avoided having to answer a range of corruption allegations by claiming presidential immunity.
A court late last year confirmed that he would not have to face questioning for the duration of his office.
But any new revelations could dent his chances of election victory.
The latest opinion polls suggest the Schuller affair has already taken its toll, putting Mr Chirac for the first time neck and neck with his likely rival, the Socialist Prime Minister Lionel Jospin.
Some of Mr Chirac's supporters have already suggested that the timing of Mr Schuller's discovery is too advantageous to the Socialist Party to be merely coincidental.
Former right-wing Foreign Minister Alain Juppe claimed that the government had "orchestrated" the Schuller case "to cover up the left-wing's coalition's track record, which is awful".
A Socialist Party spokesman rejected the claims as "paranoid and scatalogical delirium".