A flag mix-up caused Canada a bit of embarrassment today — day one of a state visit by the king and queen of Belgium, the first such visit in over 40 years.

Belgian journalist Wim Dehandschutter was the one who first pointed out that the flag marking a tree Belgium's Queen Fabiola planted on the grounds of Rideau Hall back in 1977 was actually Germany's flag.

Both flags feature black, red and yellow or gold bands, but Belgium's stripes are vertical while Germany's are horizontal.

"While we were preparing for the tree planting ceremony on the grounds of Rideau Hall, it was brought to our attention that there was a mix up with a small flag," said Marie-Ève Létourneau, a spokesperson for Rideau Hall.

"We rectified the situation immediately, prior to their majesties' arrival at the tree planting."

Belgian Foreign Minister Didier Reynders was unfazed by the flag faux-pas.

"They are the same colours so maybe that's the reason why, and we have very close relations with Germany so it's not a real problem," he told the CBC's Terry Milewski on Power & Politics.

But Dehandschutter said the Belgians are taking the trip to Canada very seriously. King Philippe and his wife, Queen Mathilde, are being accompanied by seven ministers, 100 business leaders and representatives from Belgium's universities, he said.

'It's a big mistake'3:33

"The German flag, it [will] make the headlines in Belgium newspapers and in websites, so people are talking about it," he said.

"It's a strange story. Why do you confuse the German flag with the Belgium flag? Theoretically, it's a big mistake by the Canadians."

The royal couple, whose official title is King and Queen of the Belgians, today planted their own sugar maple tree at Rideau Hall and placed a wreath at the Tomb of the Unknown Soldier at the National War Memorial.

On Tuesday they're scheduled to attend a ceremony where, in honour of the conclusion of centennial commemorations marking the end of the First World War, a cannon used during that war will be handed over to the Canadian War Museum.

The monarchs also will visit Toronto and Montreal during their tour. They do not have any scheduled visits with Prime Minister Justin Trudeau.
Cda Belgium 20180312

King Philippe and Queen Mathilde of Belgium sample freshly-made maple syrup taffy at Richelieu Park Sugar Shack during a state visit to Ottawa on Monday, March 12, 2018. (Justin Tang/Canadian Press)

With files from the Canadian Press