Did someone spot you some money for lunch two weeks ago? In France, Twitter users can now publicly repay debts, donate to charity or chip in for a gift with a new payment service backed by the country's second-largest banking service.

Group BPCE, which includes Banque Populaire and Caisses d'Epargne, announced the service — called S-money — on Tuesday.

Users tweet a payment request to S-money, which then requires an authentication code before sending the amount — and a tweet to the destination confirming payment for all the world to see.

Armand Dos Santos, chief technical officer for S-money said: "We think that this is quite interesting for the Twitter user to be able to communicate the financial transactions that he has made."

The service only works between French users.