Meal vouchers/titres-repas

Who told you that misinformation?
Most companies have moved over to electronic card now. You use the card or vouchers to pay for any food in supermarkets or in restaurants (not all restaurants yet accept the electronic cards). They are very simple to use.

you case use them in almost all supermarkest, also depending on the mood of the cashier you can get away with them for some non-food products.

some butchers also take them if you want to buy meat.

street markets stalls tend not to accept them.

Also many restaurants accept them if you decide to go for a cafe lunch, be aware they have short life span and if out of date you lost them.