Public Works Canada and the National Capital Commission appeal to the Ontario Municipal Board...

when they disagree with  municipal planning decisions.
Examples:
1.)  The Dominion Public Building, 1 Front Street West, Toronto, Ontario.
1 Front Street West, City Initiated Zoning Amendment - August 15, 2017.
"During the drafting of the Former City of Toronto Official Plan in the early 1990's and the associated amendments to the zoning by-law 438-86, the height limit and density limit on this property were reduced to more closely reflect the height of the existing heritage building on the property.
 As a result, Public Works Canada, on behalf of the Crown, appealed the changes to the Ontario Municipal Board,"

2.)  The Moffatt Farm, an 88-acre parcel of Veteran's Affairs land that eventually became a much-loved park. The City of Ottawa wanted to preserve the green space.
Scouts not prepared for NCC - July 5, 2002.
"Sources tell us a troop of Scouts that had been leasing land from the NCC for camping at Moffatt Farm were forced to vacate about a month ago due to a significant increase in lease charges. The Scouts had built at their own expense, two small buildings to store their equipment but they have been instructed by the NCC to remove the contents of the buildings, which were then demolished. The NCC hopes to sell the land for development, although the City has refused to re-zone the land and the case is still before the Ontario Municipal Board." (From: NCC Watch.)  (Note: The land was sold to a real estate company that produced a subdivision called "Prince of Wales on the Rideau" near Mooney's Bay. Moffatt Farm was part of the Rideau Canal waterway system.)

3.) The NCC contacted the Ontario Municipal Board over disputes with the City of Ottawa over zoning for "Concord and Echo" "Innes and Blair" and "Heron and Walkley". "Each time we were successful at the OMB because OMB felt the city was not being fair as far as zoning was concerned." (From: "Standing Senate Committee on National Finance - June 11, 2002.)