The Elizabethan Church of England is organised as a hierarchy, with the Queen and Archbishop of Canterbury at the top. Lay people, people who are not ordained clergymen, usually have little say in what goes on.
The French refugee churches are more democratic. Each church has a consistory to run its affairs. This is made up of the local ministers and a number of elders who are elected by the congregation. A colloquy is a gathering to which a number of consistories send delegates. This system is already in place among the Reformed (Protestant) churches on the Continent.
By holding a colloquy the Huguenots have taken a step towards developing their own system of government, independent of the Church of England.