Eagle-eyed veterans and soldiers knew right away that something was amiss as the man was being interviewed during CBC's live coverage of Tuesday's events near the National War Memorial.
Various media reports have cited complaints about the style of the man's beard, the type of beret on his head, the positioning of his medals and badges and the fact that he wasn't wearing a sash during the interview.
It is a crime under the Criminal Code to impersonate a soldier.
After initially saying they had not received a formal complaint, Ottawa police issued a tweet Thursday to say that they would be launching an investigation following "numerous inquiries" about the man.
"The man possibly made unlawful use of military uniform or certificates at the Remembrance Day ceremony in Ottawa," said the tweet.
Earlier in the day, an Ottawa police spokesman said no one had filed a complaint about the man, whose appearance on television reportedly prompted a number of complaints from veterans and soldiers alike.
During a live CBC interview, the man identified himself as Franck Gervais — but the Department of National Defence says it has no record of anyone by that name.
The public broadcaster has since issued a statement expressing regret about the interview, saying it would be "following up to learn more about the man."
The Defence Department issued a terse statement.
"Members of the Canadian Armed Forces take great pride in wearing their uniforms," National Defence spokesman Daniel Le Bouthillier wrote in an email.
"Such activities are a disservice to the proud men and women of the Canadian Armed Forces, who earn the right to wear their uniforms for the hard work and sacrifices made for our country."