The officer, Davi dos Santos Ribeiro, was detained soon after Monday's incident, before being freed by a court the following day.
He has been placed on desk duty. The policeman "does not have the psychological conditions" for street patrol work, the judge ruled, although he stressed the officer's clean record prior to the "tragic incident."
The shooting took place in Rio's gang-plagued Rocinha favela, when officers say they opened fire on a car breaking through a security cordon, not knowing that it carried tourists. A Spanish woman died of her wounds in hospital.
Earlier, police from an elite unit fought with drug gang members in two locations in Rocinha, a favela that has long been almost beyond the control of the authorities.