Je ne sais what?!

Ahead of hosting the 2024 Summer Olympic Games, Parisian cafes and brasseries have launched a ploy to con unaware tourists — and even locals — out of some extra euros.

Foreigners coming to the City of Light are showing a lack of awareness that tipping culture in France is much different than in the US and other nations. Since there is a legally mandated 15% service charge and menu prices are often higher to cover workers’ wages, it is customary only to leave about 5% extra tip — known as pourboire in French — at best.

But the five interlocking rings — and 15 million anticipated travelers — coming at the end of July are inflating that minute number, according to experts and residents.

French restaurateurs are playing into their international guests’ ignorance by nudging them to pay forward like they would at, say, a stateside Applebee’s, The Times of London reported.

“You can only think that this is a way to get the French to leave bigger tips or to get foreigners to give as much as they would in their own countries,” said a “very surprised” Bordeaux University professor Olivier Babeau.

“And it’s not totally absurd to imagine that this new practice is linked with the Olympics.”

The Times added that restaurant owners are apprehensive that tourists will be lodging outside of the city limits or will cut costs by eating French-loved American fast food.

They also worry people won’t eat out when they watch the games this summer. London restaurants suffered a dip in business during the 2012 games.

In response, the Paris food scene is taking a s’il vous play from the American arena — tablet-style guilt tipping with preset, lofty options.

“With the waiter watching while you make your card payment, you feel very uncomfortable if you don’t add a tip,” a 35-year-old doctor named Arnaud told the Times.

“I’ve been shocked in the past when I’ve seen waiters asking foreigners for tips,” added Françoise, a 55-year-old television producer.

But restaurants aren’t differentiating foreign from local — and it’s a major faux pas, he said.

“They were just taking advantage of them because they didn’t know that service is included here. That’s bad enough, but it’s scandalous that they’re doing it to us, too.”