All registered players in France (they call them "licensed", but it amounts to the same thing) have a "colour". Women who have been playing for less than four years are "orange", players who have been playing for longer - and have also been at the same club for more than four years - are "white", but any player who has moved clubs within the last four years is "white-yellow".
There are then strict limits on the number of "white-yellow" and "orange" players a team can field in any league game.
- A maximum of 7 "white-yellow" in a squad of 22 (6 in a squad of 21, 5 in 20, 4 in 19 - you cannot play with a squad smaller than 19).
- A maximum of 11 "orange" players in a squad
Its an interesting idea as it means that large, successful clubs like Perpignan cannot sign up every promising player in their region - thus effectively killing off rival clubs - but instead have to base their game around players who have been at the club for four years or more. To an extent it ensures that talent is spread around as a player wanting to move will steer away from a club with a lot of recent signings. In essence you cannot "buy" success.
It can make things difficult for clubs newly promoted to higher divisions, especially if they have relatively small squads, or where a significant number of players retire together (a problem faced by RC Chilly last year), but all in all it seems to work. After Perpignan were caught early last season, no other club suffered similar fines.
It would be interesting to speculate how a similar system might work in England, at junior or senior level. At the very least it would encourage clubs to register their players in the first place - and keep the registrations up-to-date!