FX v GZ
Council Regulation (EC) No 4/2009 of 18 December 2008 on jurisdiction, applicable law, recognition and enforcement of decisions and cooperation in matters relating to maintenance obligations is to be interpreted as meaning that an application opposing enforcement brought by the maintenance debtor against enforcement of a decision given by a court of the Member State of origin and which established that debt, which has a close link with the procedure for enforcement, falls within its scope and is within the international jurisdiction of the courts of the Member State of enforcement.
Pursuant to Article 41(1) of Regulation No 4/2009 and to the relevant provisions of national law, it is for the referring court, being a court of the Member State of enforcement, to adjudicate on the admissibility and the validity of the evidence adduced by the maintenance debtor, seeking to support the submission that he has predominantly discharged his debt.