Mutual Polity
...the two federations [the Dutch and French] also subscribed to each other’s church polity, “as a proof and testimony of the mutual agreement of all the churches of both federations, as much in doctrine as in good order.” They also opened their pulpits to each other’s pastors and the French decided to send deputies to the Dutch synods.
Theodore G. Van Raalte, "The French Reformed Synods of the Seventeenth Century", in Martin Klauber, ed., The Theology of the French Reformed Churches: From Henry IV to the Revocation of the Edict of Nantes (Grand Rapids, MI: Reformation Heritage Books, 2014), 93-94