Over 3,000 people have signed a petition calling for a mural in Smithfield not to be painted over.
An Bord Pleanala is to decide whether or not to grant planning permission for the 'Horse Boy' mural to remain.
It's located just off Church Street, and was painted by members of the Subset art group two years ago.
It said the city council had allowed it as a temporary installation as an "exempted development" because it had the blessing of city management.
But there was a 12-month time limit on the permission, and it ran out in April 2018.
Green Party Dublin MEP Ciarán Cuffe says the mural should stay.
"I think a public petition is a good way of focussing attention on people's views and people's feelings," he said.
"I think there's a lot of local support for this mural, they see it as being part of what they are and part of what the city is," he said.
