A journalist in Nice stopped by the local Restaurant le Petite Syrah and snapped a picture of its menu board. It outlined a very specific set of rules for how coffee would be priced.

Say, “Hi, a coffee, please,” and your espresso will cost about $2, a typical price in France. A customer who doesn’t say hi but does say please gets charged about triple the price — almost $6. And for a rude customer who comes in and grunts “coffee,” the price is almost $10.

In other words, there’s a politeness discount; the price drops four bucks for every increment of courtesy.

But the Guardian found that it’s more of a nudge than a serious pricing policy:

Pepino said he had not yet had to enforce the politeness policy, and admitted the sign was more of a gentle reminder than a serious threat.

“It started as a joke because at lunchtime people would come in very stressed and were sometimes rude to us when they ordered a coffee,” Pepino told the English language website the Local.

And you probably aren’t going to get far by telling a caffeine-deprived, grumpy person that their grumpiness just cost them $8. But, Pepino told the Local, the sign is doing the work on its own: People are smiling more. And saying please.