The breach of the code of conduct, however, carries no penalty.
Karen Shepherd, the commissioner of lobbying, said Keith Beardsley, a veteran political staffer, broke the rules in 2009 when he tried to arrange a meeting between Guy Giorno, then the prime minister's chief of staff, and a wireless telephone company.
Giorno immediately contacted the lobbying watchdog.
Shepherd ruled that Beardsley was prohibited from lobbying at the time he made the call.
Certain office holders are barred from lobbying for five years after they leave government. Beardsley left the PMO in 2008 and won't be clear to lobby until 2013.
"I found that, for payment and on behalf of a client, he attempted to arrange a meeting with a public office holder, which is an activity that requires registration by consultant lobbyists," Shepherd said in her report.
In May 2010, Shepherd sent the file to the Mounties.
"The RCMP advised me, in a letter received on December 13, 2010, that they had decided not to lay charges, as they did not have sufficient evidence to determine payment," she wrote.
"Despite the RCMP's decision not to proceed, I determined that I had sufficient grounds to continue with a Lobbyists' Code of Conduct investigation."
Beardsley is a partner in an Ottawa consulting firm, True North Public Affairs. He has a long pedigree in government.
"His work experience in the federal government has included assignments as ministerial chief of staff and senior adviser in three federal departments, as well as deputy chief of staff to Prime Minister Stephen Harper," the report said.
"He also served as the head of research for the Progressive Conservative party and was a senior adviser in the office of the leader of the Opposition."
Another Harper adviser, Bruce Carson, is under investigation by Shepherd for allegedly approaching public office holders about a water project his girlfriend was involved in without registering as a lobbyist.
Shepherd found last year that former Conservative MP Rahim Jaffer and his former business partner violated provisions of the Lobbyists' Code of Conduct.
However, Shepherd's office has just two avenues: try to educate those who make minor slip-ups, or refer more serious matters to the RCMP.
Last month the House of Commons ethics committee recommended that the lobbying watchdog have the power to fine rule-breakers.
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