The Grand Prix is back, almost, and this year it's bringing with it a slew of ads at bus stops across Montreal, Laval and Longueuil.

"Paying for sex is illegal in Canada," the ads say -- an effort to remind tourists of the local laws.

But sex workers and those who represent them say this is the wrong kind of messaging, and it could backfire, creating a climate of secrecy that gives them less control.

"If the message our clients are getting is 'you’re going to be arrested if you buy sex,' then it become the sex worker's responsibility to make the client feel safe," said Sandra Wesley of the group Chez Stella.

"That means obviously we can’t be asking for IDs, negotiating," or doing other things that help sex workers keep themselves safe.

Wesley said the majority of sex workers are doing their jobs by choice and the ad campaign is one more effort to eradicate sex work.

"Attacking our clients, attacking third parties in the industry only puts us in further poverty, only marginalizes us further, and makes it harder for us to have options," she said.

Meanwhile, for the minority who are forced into it, what's needed is better social services, not threatening ads, she said.

The ad campaign is a partnership between the Quebec government and CLES, an organization that fights sexual exploitation.

Jennie-Laure Sully, who works with that group, sees things differently.

"Violence is the norm and not the exception in that industry, and there is no way to make it really safe, and legalization is not the answer," she said.

She believes, unlike Chez Stella's position, that the majority of sex workers have been forced into the industry, and that that needs to be made clear to those who pay for sex.

“By targeting the client for which that system exists, it is possible to reduce the demand," she said.

Wesley argues that reducing demand harms those who depend on this work for their livelihood.

"The solutions will never come from people who oppose the entire sex industry, the same way that anti-racist policy will never come out of racist groups," she said.

A better ad campaign, she says, would be one teaching clients how to treat sex workers with respect.