The Republic of Ireland edition of the Irish Daily Star has published photos of the Duchess of Cambridge sunbathing topless while on holiday in France.
Editor Mike O'Kane said he treated Catherine as he would any celebrity.
But the paper's joint owners - Northern and Shell and Independent News and Media - condemned the decision and said they had no prior knowledge of it.
St James's Palace has said it is suing the publishers of French magazine Closer which first printed the images.
A palace spokeswoman said of the Irish publication that there could be "no motivation for this action other than greed".
The pictures did not feature in the Northern Ireland edition of the Irish Daily Star.
'Service to our readers'
The Dublin-based tabloid is a joint venture between Northern & Shell - publisher of the UK Daily Star - and Ireland's Independent News and Media.
Following publication of the photos, Northern and Shell said it had no editorial control over the Irish-based newspaper and was consulting lawyers "as a matter of urgency", over what it believed to be "a serious breach of their contract".
Chairman Richard Desmond said: "I am very angry at the decision to publish these photographs and am taking immediate steps to close down the joint venture.
"The decision to publish these pictures has no justification whatever and Northern & Shell condemns it in the strongest possible terms."
Independent News and Media added that it had no prior knowledge of the matter prior to publication.