The announcement came after the 14-year-old girl's lawyers accused authorities of "disproportionate" measures against teenage protesters seeking fully free leadership elections.
The girl was arrested last week for chalking a flower on the "Lennon Wall" and sent to a children's home Monday for three weeks as a court considers whether to remove her from her father's care.
The application before the court alleged that she is being neglected by her family but the girl's lawyers strongly rejected the charge citing a lack of evidence.
The police spokeswoman said that the girl has been released on bail before her case is heard again on January 19.
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The girl's lawyer, Patricia Ho, said earlier that the decision to place minors in children's homes was usually only undertaken in extreme cases and was an attempt by authorities to "impose a climate of fear".
The "Lennon Wall" is a staircase by a major thoroughfare in Admiralty district which was blocked by democracy protesters during more than two months of rallies and plastered with brightly-coloured notes of support for the movement.
In a separate case, a 14-year-old boy could also be removed from his parents' care after being arrested when police cleared a protest camp in Mongkok in late November.