In July 2015, Poilievre announced an expansion of a child care benefit program. During the announcement, he wore a Conservative Party of Canada shirt, stated that the payments were from "our Conservative government", and said that "if the Liberals and NDP were to take office they would take the benefits away and raise taxes." Later in 2017, the elections commissioner determined that the occasion was akin to a Conservative party campaign event, rather than a Government of Canada announcement. As the government spent approximately $4,800 related to the event, it was essentially "a de facto non-monetary contribution" to the Conservative party. The commissioner ruled that this was a campaign finance violation, as Poilievre had "knowingly circumvent[ed] the prohibition on contributions to a registered party by ineligible contributors." Poilievre was ordered to post a link to the ruling on his social media.
His claim of violating the Elections Act seems to be when he wore a party t-shirt to a gov announcement https://en.wikipedia.org/wiki/Pierre_Poilievre