The rule is called 'en prison' ,which means if you play red or black and the zero comes out, your jeton is place 'in the prison' for the next spin. If there you hit your color you get half of the win back. So if you would play €2, instead of the normal €2 win they pay you just the €1. Me and Rich had to negociate a lot in Castillo Perelada just to get a €1 jeton each. Like you understand they don't have a lot of these.
Also like said by Robert Touts, a bit lower in this thread, a €0,10 or 0,20 to sell at face knowing that a jeton costs at least €3 to €4 to make it is even worse than a 25cent$ chip costing 70cent$ to make.
But true, I have never seen such small denomination jetons, but again I don't play Banque in Paris either. Hope to play La Boule in Switserland next wednesday and thursday though.
Kind regards,
Belgium Bob R-4479

ps : Fran can explain the 'en prison' rule in detail as he uses it at 'his' French Roulette table