Until now, Berlin had not said when it might try to recuperate the billions of euros injected last year into the country's second-biggest bank to keep it from collapsing amid a financial sector crisis.
Commerzbank soaked up €18.2 billion ($23.7 billion) in public funds as it struggled to integrate loss-making Dresdner Bank, leaving Berlin with a stake of more than 25 percent.
"Nothing is worse than a state holding in banks. It must remain an absolute exception," Brüderle told business daily Handelsblatt.
To pay back the public money, Commerbank might make a capital increase this year if the market is stable, unidentified banking sources cited by the daily said.
The bank is to release second-quarter results on Thursday.