The ruling applies only in countries where gay couples can marry or register legally recognized unions, Deutsche Welle reports. The court also left it up to courts in member states to decide whether same-sex couples have rights that are the equivalent of heterosexual spouses.

The case was brought by Tadao Maruko, the registered partner of a German costume designer who died in 2005. The European court found that he had suffered discrimination because German law, while it does not recognize gay marriage, gives registered partners equivalent rights.

A German court must still make the final ruling.

The European Commission welcomed the court decision but said the countries in the union still have control of laws on marriage.

"It's not the commission or any other European institution that imposes on Germany or any other member state whether or not marriage or registered couples must be treated equally," a spokeswoman said.