A méreau coin, or communion token, was distributed to parishioners deemed worthy of taking communion. During the Huguenot persecution, they acted like a password to exclude infiltrators who may have wished to spy on the congregation.
Each reformed Protestant parish had its own design, often fairly naïve in style. The méreaux, or communion tokens, were kept by the anciens or elders, and distributed by them to those parishioners considered worthy of approaching the Lord's table - i.e. to take communion. This would not have been a weekly occurrence, and the méreaux would have been collected up by the anciens afterwards.
In times of persecution, like a password, they served to exclude infiltrators who may have wished to spy on a congregation, especially during the period of the église du désert, when services were being held clandestinely out of doors. They were withheld from a parishioner under censure for some misdemeanour, and not returned until the church consistory was convinced that person had mended their ways.
In some cases, there is evidence that a méreau was withheld if a parishioner had consistently not paid his quarterly contribution towards the minister's salary, or towards poor relief for the community. Méreaux sometimes served therefore as a disciplinary tool, a kind of temporary excommunication, as well as a means of protecting a congregation.
Barbara Julian, President of the Huguenot Society