It is thought the five primates used wood that had fallen into their pen from recent gardening work to climb out and run for freedom at Hannover's Experience Zoo.
The five-year-old girl sustained light head wounds after she was apparently knocked down by one of the marauding chimps. She was taken to hospital as a precautionary measure.
Four of the five escapees "had a quick look around and then jumped pretty quickly back into their compound," said spokeswoman Simone Hagenmeyer.
"The fifth and oldest chimp went off to visit the head gorilla," she said, adding he was a bit harder to cajole back to captivity.
"He's getting on a bit, so we offered him a ladder to get back into the enclosure," she said.
Some 2,500 people were evacuated from the zoo in the northern city of Hannover while the escape bid was quashed, the spokeswoman said.