"I personally find Holocaust denial deeply offensive," Zuckerberg stressed.
Arthur Jones was questioned about his views and website, which he claimed was not racist.
Arthur Jones has made no secret of his view that the Holocaust is a "racket," and he has even made that a prominent part of his latest bid for public office.
Currently the Sephardi chief rabbi of Jerusalem, he has a history of attacking liberal Jews as "evil" and homosexuals as a "cult of abomination."
"This is rather disturbing and disrespectful," the Auschwitz Museum and Memorial had tweeted.
After two major Holocaust gaffes by his administration, President Donald Trump gave the keynote address at the Days of Remembrance ceremony.
Benoit Loeuillet claimed that he had not denied the "reality" of the Holocaust.
An exhibition of 150 submissions is now up in the Iranian capital, as Germany, Israel, UNESCO and others condemn the contest.
Iranian leader questioned the Nazi regime's mass murder of Jews on Holocaust Remembrance Day.