If the action is brought in Spain, Regulation 4/2009 will apply to determine jurisdiction, except for residual cases.
This Regulation confers international jurisdiction on the Member State in which the maintenance creditor (irrespective of where the debtor resides) or the defendant (who is sometimes not the debtor) resides.
The courts of the Member State of the European Union which is seised of the parentage or parental measures (parental responsibility) shall also have jurisdiction, unless such jurisdiction is based solely on the criterion of the nationality of the plaintiff.