Commerzbank said in a statement it booked net profit of €78 million in 2013, compared with a loss of €47 million a year earlier.
But operating profit slumped to €725 million euros from €1.17 billion euros a year earlier.
All sources of income were lower, with overall revenues falling 5.9 percent to €9.269 billion.
Of the different revenue components, net interest income was down 5.2 percent at €6.148 billion and net commission income slipped one percent to €3.215 billion.
Net trading income showed a loss of €82 million and net investment income was down 79 percent at €17 million.
Chief executive Martin Blessing described 2013 as a "year of transition".
He said: "We have attained a solid operating profit in both the group and the core bank. As announced, we have invested in our growth and, at the same time, further lowered our costs. We have been able to implement as scheduled what we had planned for 2013."
The bank said it had set aside €1.747 billion in loan-loss provisions, up 5.2 percent over a year earlier.
At the same time, operating expenses fell by 3.3 percent to €6.797 billion.
Commerzbank had made progress "considerably more quickly" in its reduction of non-core assets and "we have increased the core capital ratio to nine percent one year earlier than planned," Blessing said.
On top of this, the bank had repaid in full the silent participations of the German government and Allianz, and further strengthened its capital base.
Looking ahead, Commerzbank said revenues would "still probably be impacted as a consequence of the low interest-rate environment and the low level of investment activity on the part of companies".
This year, loan loss provisions should be lower than the overall figure for 2013 and operating expenses "should not exceed €7 billion," the bank added.