Face of Nation : The content on Fodor’s Travel website and in their books on Ireland, said nationalist murals “often aspire to the heights of Sistine Chapel-lite”.
It said loyalist murals “sometimes resemble war comics without the humour”.
The content was also used by Singapore Airlines in their travel guide.
Prof Peter Shirlow, head of Irish Studies at Liverpool University, criticised the city guide.
“I found some of the commentary to be offensive, if not sectarian,” he said.
“It plays upon sectarian myths of identity and culture in Northern Ireland and has failed in any way to deal with the murals in ways that is either balanced, appropriate or ultimately fair.”
In a statement to BBC News NI, Fodor’s Travel said the content has been removed from their website Fodors.com and would be removed from the ebook version of its guide to Ireland within the week.
“We will also ensure that the content is removed and updated for the next print edition of Fodor’s Essential Ireland, which will be released on September 8.
“Fodor’s Travel is always listening to the feedback we receive about our content, and we take action when we’re notified of content that is outdated, inaccurate, or insensitive by updating and/or removing that content.”
On loyalist murals, the guide said: “Recently, Protestant murals have taken on a grimmer air and typical subjects include wall-eyed paramilitaries perpetually standing firm against increasing liberalism, nationalism and all the other -isms Protestants see eroding their stern, Bible-driven way of life.”
The guide described murals in nationalist areas as featuring “themes of freedom from oppression, and a rising nationalist confidence that romantically and surreally mix and match images from the Book Of Kells, the Celtic mist mock-heroic posters of the Irish artist Jim Fitzpatrick, assorted phoenixes rising from the ashes and revolutionaries clad in splendidly idiosyncratic sombreros and bandanas from ideological battlegrounds in Mexico and South America.”
Author and commentator Fionnuala O Connor said the guide had a “republican triumphalist ring to it”, and is “patronising and sneering at loyalists”.
“The idea that loyalists are protesting in defence of a ‘stern, Bible-driven way of life’ has the ring of someone with one eye on an old social history and little to no sense of life now in loyalist districts,” she said.
“It is far from Bible-driven. This is slanted in a way which leaves a sour taste in modern Belfast.
“There’s a nasty edge. Singapore Airlines should ask the writer for their money back.”
Referring to the “grimmer air” the airline’s guide stated loyalist murals had taken on, Prof Shirlow said the “reimagining” of Protestant murals had led to fewer paramilitary themes and instead a greater focus on community celebration, gender issues, peace building and “non-sectarian identity tropes”.
“The text is, based upon the evidence that I hold, unacceptable and could potentially facilitate a sectarianised narrative,” Prof Shirlow added.
In a statement Singapore Airlines said: “We understand from our in-flight entertainment system providers that the content for the in-flight guide was provided by Fodor’s travel guides for use on board by airlines.
“However, we note your feedback and have gotten in touch with the agencies involved and are taking steps to review the content in the in-flight guide.”
