Also:
Residential Rental Administration
Residential Rentals Authority
Residential Tenancies Authority/Administration
Rental Housing Administration
etc.

Examples:

http://www.dcwatch.com/council16/16-457.htm#summary
RENTAL CONTROL REFORM AMENDMENT ACT OF 2006
Executive Summary
The Executive’s rent control proposal incorporates the desires of tenants, housing providers and the District’s *** rental housing administration *** by converting the current rent ceiling system into a rent charged system. The following summary details the ways in which the Executive’s approach benefits all parties.

http://www.irac.pe.ca/rental/
Office of the Director of Residential Rental Property, Prince Edward Island, Canada

http://www.rta.qld.gov.au/index.cfm
Residential Tenancies Authority
Achieving fair rental outcomes in Queensland

http://www.gov.ns.ca/snsmr/consumer/resten/
Residential Tenancies - For Nova Scotia Landlords and Tenants