A Montreal man is questioning the sales practices of some McDonald's restaurants, claiming employees are upselling coffee unbeknownst to customers.

“It's the principle at play here,” said Mark Julien

Julien said he noticed one morning when he stopped at a McDonald's for breakfast that he was being charged $6.40 for his $6 breakfast trio.

“I was a little peeved on that for sure,” he said.

The trio comes with a small coffee – a medium costs 40 cents more.

Julien decided to test it out and went to three different drive-throughs -- two on the island of Montreal and one on the South Shore.

He got the same question each time: “Medium?” the employee would say when it came to his coffee.

None of the restaurants chose to tell him that the medium coffee costs more.

“My biggest pet peeve, with this whole thing, is that if you're going to want to upgrade a coffee, at least make it a decision the person can make. Just saying ‘medium’ to a client isn't giving them a choice; it's forcing a choice upon them, and that takes away our buying power,” said Julien.

Consumer laws dictate that merchants must mention any important fact when selling a product – so if that 40 cent price hike could be a deal breaker, they should say it.

“The best practice would be for a merchant to mention it is an upgrade and that some extra charge would be added,” said Sylvie De Bellefeuille of consumer group Option consommateurs.

A spokesperson for McDonald's Canada said there is no corporate pricing strategy or directive about this practice, adding that it might just be because the medium size is the best seller.

Forty cents probably wouldn't have changed Julien's decision to stop at McDonald's, but that’s not the point, he said.

“Everybody is just squeezing a bit more and a bit more and a bit more,” he said.

“It's an enormous profit maker,” said Harold Simpkins, a marketing professor at the John Molson School of Business.

Upselling an issue in many industries, he said, including cable companies, car dealerships and insurance firms.

“You kind of get the deal done, and they say, ‘Oh, by the way, do you want to get your deductible down to zero from $500? It's only $6 a month more,’” he said.

McDonald's said even if a few franchises are doing it, there's no indication it's an issue beyond that.