Sylvie is a tax inspector, one of 10,000 financial experts who have volunteered to go into schools to explain the workings of the Euro, the common currency which most members of the European Union will adopt from January 1, 1999. Cheques, bank accounts and bank cards will convert first and by 2002 the franc will no longer be legal tender.
The government hopes that receptive youngsters will take their Euro expertise home and explain it all to their families.
Even Dominique Strauss-Kahn, the economy minister, took time off to explain the changeover to a class in Sarcelles, the town where he used to be mayor.
The financial civil servants have so far visited 15,000 classes - a total of 400,000 primary pupils - and next it will be the turn of the secondary schools.
With posters attached to the blackboard, Ms Barreau discusses with the class how the EU began, what countries are members and their present currencies. She moves on to the calendar for change and converting francs into Euros, handing out sheets picturing cut-out versions of the seven banknotes (featuring bridges and windows to symbolise communication and "opening up") and eight coins representing Euros and cents.
The children want to know whether shops will take advantage of customers' ignorance and overcharge; why some people are against the change. And will it affect their pocket money?