Belfast City Council has confirmed it received a complaint after an Alliance Party worker donned the Lord Mayor's chain - and quipped his first act would be to ban the DUP from the city.
Micky Murray, who works for South Belfast MLA Paula Bradshaw, published a post to his Facebook page last Friday in which he is standing in the Lord Mayor's parlour wearing the chain of office.
Mr Murray's party colleague Nuala McAllister is the current Lord Mayor of Belfast.
He added the message to his post: "As First Gay of Belfast it's an honour to invite the LGBT community to Belfast City Hall for the launch of Belfast Pride.
"My first act as First Gay of Belfast is banning the DUP from the city and making rainbows compulsory."
In an exchange of comments on the post - which is visible to any Facebook user and not restricted - Mr Murray added: "I've claimed it."
Alliance leader Naomi Long is among almost 450 people who 'liked' the post, as well as Ms Bradshaw, and Alliance councillors Emmet McDonough Brown and Sian O'Neill.
However, a complaint has been made to the council over the post, questioning whether such a statement was appropriate.
The same person also contacted the Belfast Telegraph with their concerns, claiming that they found the post to be disrespectful to the Lord Mayor's chain of office, and also to the DUP.
The DUP also hit out, saying the post was a "misjudgment".
Party Belfast City Council group leader Lee Reynolds said: "Whether he meant it as a joke with a jag or as a real comment, it is not acceptable and an insult to the tens of thousands who vote DUP in Belfast.
"The use of a photograph in the Lord Mayor's chain alongside this statement adds to the misjudgment by this Alliance Party employee and the Lord Mayor herself."
The Alliance Party said it did not wish to respond.
Belfast City Council confirmed it had received a call about the Facebook post, but that the matter had been resolved within the phone call and it regarded the matter as closed.
The chain of office dates from 1874, when it was purchased and presented to then Mayor James Alexander Henderson.
It displays the city's coats of arms and the motto is surrounded by symbols representing the four provinces of Ireland.