City vs borough councillors: what’s the difference?

Le Devoir has a piece on the distinction between city councillors and borough councillors and what their jobs involve.

It’s mentioned here, but bears repeating, that we get several ballots in the municipal election, but there’s no obligation to vote a straight party line. The mayor is elected via direct popular vote, not because their party wins the most seats as in a parliamentary system. You’re free to mix and match.

Which makes me wonder – historically, have we ever had a situation where the mayor was presiding over a council dominated by an opposing party?