Developer Ray Grehan is one of nine property owners served with enforcement notices by Dublin City Council for running unauthorised car parks.
Iarnród Éireann has also been issued with a warning letter for running a car park at Connolly Station that the Council says breaches planning permission.
Mr Grehan has been running a 200-space car park at the former veterinary college site in Ballsbridge, which he bought for more than €170m four years ago.
Mr Grehan was previously issued with a warning letter and was quoted as saying that he intended to appeal, as he believed there was permission for a car park.
An enforcement notice is the last step before a prosecution for breach of planning laws which allow maximum penalties of a €10m fine or two years imprisonment.
The eight other properties served with enforcement notices include Molesworth Street Car Park, a carpark on the Carlton Site off Moore Street and Findlater House also near O'Connell Street.
Warning letters, which are the first step in planning enforcement, were issued against nine properties including a car park at Connolly Station.
A spokesman for Iarnród Éireann said the company would be appealing the action.
