The young men shouted "extra, extra" while waving copies of the The Flanders Fields Post, which contained a summary of the war's key events.
One of the newsboys said he was glad for the chance to educate people about Canada's role in the First World War.
The event was sponsored by the Belgian government.
"We want to show our appreciation and our thankfulness for the Canadians," said Line Vreven of the Flanders tourist office.
She said similar re-creations were being staged in Dublin and Manchester.
"This is how they would have announced the war and distributed the newspapers back in 1914," she said. "It was word of mouth and hearing the paperboys yelling in the street and trying to sell their newspapers that you were aware of what was going on in the world."
About 620,000 Canadians enlisted during the First World War and about 419,000 went overseas. About 60,000 never came home.
The war was considered a turning point in Canadian history, when the country shed its colonial mindset to become a nation in its own right.