A German court ruled, that the GNU Public License (GPL), a common license for open source software distribution, is legally binding:

Das Landgericht Frankfurt hat Anfang September erstmals in einem Hauptsacheverfahren mit Beweiserhebung die Gültigkeit der GNU General Public License (GPL) bestätigt.

Read the full news by Heise and the reasoning by the court (both in German).

Thereby a previous judgement to the same extent by Landgericht München in 2004 with the reasoning (both in German) is confirmed and supported.