The statute text
24 A landlord shall not alter the locking system on a door giving entry to a rental unit or residential complex or cause the locking system to be altered during the tenant’s occupancy of the rental unit without giving the tenant replacement keys.
View this section on the official Ontario e-Laws site →
Reproduced under the King’s Printer for Ontario / Open Government Licence – Ontario. Confirm against the official e-Laws consolidation before relying on it.