Officers found the child had got out of the window in Levenshulme, Greater Manchester, due to a damaged latch.
She was taken to hospital for checks following the fall at 16:40 GMT on Tuesday but was later released.
Insp Phil Spurgeon said the child was seen "running around the hospital as though nothing had happened."
"A bump was seen on her head but the toddler was apparently otherwise unharmed... ", he said.
He added: "Given the circumstances, a detective-led review of safeguarding took place but initial thoughts are that this was an accident with a miraculous ending.
"A follow-up will be made to ensure that the landlord fixes the latch."
A toddler who fell from a second floor window "miraculously" escaped with just a bump to the head by landing on an old sofa in the garden below.