Mr Trudeau’s campaign went into damage control. He has apologised and asked Canadians to forgive him for his past behaviour.
But has it cost him support? We take a look in our regular round-up of news from the campaign.
So what do the polls say?
When the election was launched on 11 September, the Liberals and Conservatives were statistically tied in most national polls, essentially in a dead heat.
Fresh polls published early this week suggest the affair has caused Liberals support to dip – though pollsters say it’s too early to fully predict the impact.
An Ipsos poll for Global News now indicates Conservatives would win 36% of the vote compared with 32% for the Liberals if respondents were to cast their ballot at the time of the survey.
The Angus Reid Institute puts the Conservatives at 35% against 30% for Mr Trudeau’s Liberals.
“While opinions of Trudeau have worsened and as the governing party once again sees its key left-of-centre base drift, other signs show the Liberals and their leader may have enough time to recover from this embarrassing disclosure,” the research foundation said in a release.
An Abacus Data survey gave a narrower margin, with the Conservatives holding at 34% support and the Liberals slightly behind at 32%.
“Last week Mr Trudeau’s reputation was damaged, albeit perhaps less than might have been surmised or expected,” said Abacus pollster Bruce Anderson.
The margin of error for the three polls ranges from 2.3% to 2.9%.
On Wednesday, daily polling by published Nanos for CTV and the Globe and Mail indicated the Liberals were essentially tied with the Conservatives, polling at 35.3% v 35.4%.
The shift to climate
The UN’s climate summit launched this week on the campaign trail and on Friday many Canadian cities will be hosting climate strikes. Youth climate activist Greta Thunberg is expected to attend one rally in Montreal.
So there has been a greater emphasis on climate policy, with environmental issues being raised by each campaign.
The Liberals announced on Tuesday that, if re-elected next month, Canada would commit to net-zero emissions by 2050, meaning that any emissions will be offset by mitigating actions.
The NDP reiterated its plans to invest billions of dollars into climate-change measures, to end fossil fuel subsidies and to electrify all public transit by 2030.
The Conservatives said they are committed to Canada’s current Paris Agreement target of reducing greenhouse gas emissions by 30% below 2005 levels by 2030.
Liberal campaign spins its wheels
Well, the campaign media bus anyway. It bottomed out and ended up stuck on the way to an event.
This is second time transport has hit a snag – the first being when the wing of the Liberal plane was scraped by a bus ferrying journalists. The latest mishap on Tuesday in British Columbia was documented by reporters following the Liberal leader.