Today's publication of the topless photos of the Duchess of Cambridge taken at a private French chateau has provoked outrage from some quarters.
St James's Palace called the invasion "grotesque and totally unjustifiable" and believes it evokes memories of the late Princess Diana.
Closer France is published under a licensing agreement between Bauer Media and Italy's largest magazine publisher Mondadori.
Speaking to Media Week, Keenan said: "We are very disappointed, clearly, to see that the Closer brand in France has taken this editorial approach. This is not something we would do in the UK."
The magazine chief refused to go into the details about the current licensing agreement, but as with most licence agreements, the UK publisher does receive a percentage of revenues generated by Closer France.
Publishers usually maintain some control over the quality and direction of the international editions.
Keenan said: "There are broad parameters of what the magazine can do, but the brand parameters are not specific to individual stories.
"The editorial decisions are made in France by the editor-in-chief there. I am sure in the coming days, if not today, we will be talking to the management around that brand, to try and understand from them their philosophy and how they plan on taking it forward."
5.30p update when Palace announced intention to sue: Keenan added: "We are now urgently discussing this matter with our licensee and reviewing the terms of our licence agreement with Closer France."
Prior to publication of the photos, Closer's French editor Laurence Pieau promoted the issue by telling her Twitter followers, "We can say that after tomorrow's Closer, Harry will feel less alone..."
A formal statement from Bauer said: "The comments made by the editor of the French edition which have been reported in the media today do not reflect the opinions of Closer magazine UK.
"Closer magazine UK was not offered any pictures of this nature and certainly has no intention of publishing the photographs of the Duchess of Cambridge which have been published in France this morning.
"Closer magazine UK takes its obligations under the PCC [Press Complaints Commission] Code extremely seriously and would never publish topless images of a member of the Royal family on its cover or otherwise."
Evgeny Lebedev, owner of The Independent and London Evening Standard newspapers, was among those attacking the publication of the pictures.
He tweeted: "Utter disgrace that a mid-market French rag has invaded Kate #Middleton's privacy like this. Gutter press morality."
Photos again raise issues of privacy and public interest
The photographs were offered to British papers before being taken up by the French magazine. Lloyd Embley, editor of the Daily Mirror and Sunday Mirror, confirmed: "We were offered a set of pictures of the Duchess of Cambridge in her bikini about a week ago on that same balcony.
"As with the naked pictures of Prince Harry in a private hotel room, we took the decision not to publish them. In both cases we believed there would be a clear breach of the Press Complaints Commission's Editors' Code of Practice, regarding intrusion of privacy."
Today’s publication of the pictures of the Duchess of Cambridge comes during a sensitive time for the British press industry, still awaiting the recommendations of the Leveson Inquiry.
Duncan Lamont, partner in the media team at legal firm Charles Russell LLP, said: "One wonders what the approach of the UK tabloids will be when the pictures of the royal couple go viral and appear in other European publications.
"There was no justification to publish them first (the PCC Code is clear on this), but now that their privacy has been intruded into so publicly a different public interest argument can be raised-and it will be interesting to see if the copyright owner of the sneaky snaps is prepared to seek damages for the infringement of their rights by the inevitable unlicensed re-publication.
"But the Duchess will be advised that the once very strict privacy laws in France, similar to what the tabloids have achieved here in the UK courts, are being reined in by politicians and lawyers.
"Also it is not quite a private house-the Chateau is rented out and there may be debate as to how truly private it was and whether the paparazzi was on a public thoroughfare-these issues can take years to resolve.
"So the court of public opinion may seem the best bet-but all celebrities must be worried about the dam of editorial restraint bursting. Readers crave such pictures.
"Put simply, VIPs may need to remain buttoned up again."Follow @DurraniMix