Facts
[A.] and [B.] had married on 10 December 1988. The District Court of Athens dissolved the marriage of the parties by default judgment on 26 May 2003. Upon the claim of [B.] , the District Court of Willisau supplemented the divorce judgment by judgment of 13 January 2015, ordering [A.] to pay monthly child support of CHF 400 as of 1 January 2015 and CHF 1,000 as of 1 April 2015 to his daughter. [A.] appealed to the Cantonal Court of Lucerne on 13 February 2015, requesting a reduction of his maintenance obligation to CHF 270 from April to December 2015. By judgment of 8 April 2015, the Cantonal Court partially upheld the appeal and set the monthly maintenance at CHF 400 (as of 1 January 2015) and CHF 730 (as of 1 April 2015).Considerations
The Federal Supreme Court finds that the Cantonal Court has violated the appellant's right to be heard. Although the response to the appeal by [B.] was served on the appellant on 24 March 2015, the Cantonal Court rendered its judgment already on 8 April…