Catholic dioceses in Germany are hiding millions of euros in assets, according to an investigation published on Sunday by weekly paper Der Spiegel amid a scandal over a bishop's lavish lifestyle.
The diocese of Limburg's Franz-Peter Tebartz-van Elst, dubbed the "bling bishop" in the press, has been criticised for spending millions on a new building with private quarters for him.
It has received some 300 million euros ($411 million) from a religious income tax over the past 65 years and the money went into opaque financial structures, Der Spiegel reported.
The weekly said that in the particularly well-off archdioceses of Cologne, Freising and Munich, "the financial directors themselves do not know how many assets their archdiocese owns".
The scandal over Limburg's bishop has prompted several German dioceses in recent days to make their assets public in a bid to show transparency and dispel suspicions about their wealth.
In Germany, taxpayers have to declare whether they are Catholic, Protestant or neither. The religious ones are then charged eight to 10 percent more on their income tax, depending on the state, and the revenue is sent to the respective churches.
The 23 million Germans who said they were Catholic gave the Church 5.2 billion euros in tax in 2012.
The fate of the bishop of Limburg has not yet been decided but Pope Francis met last week with the head of the German bishops' conference, Robert Zollitsch, to discuss the issue.