The archdiocese of Cologne has for the first time published its financial accounts, which show assets worth more than £2bn.
Documents posted on the archdiocesan website showed assets of €3.35bn (£2.5bn) at the end of 2013.
The archdiocese has long been considered Germany's richest, and the German Church is wealthy and is a major donor to the Church’s work in Latin America.
Some € 2.4 billion (£1.8bn) were invested in stocks, funds and company holdings. A further €646m (£475m) were held in tangible assets, mostly property. Cash reserves and outstanding loans amounted to about €287m (£211m).
In 2013 the archdiocese received €573m (£421m) from church tax paid by the 2 million Catholics living in and around Cologne, the Associated Press reported.
Catholics in Germany have to pay between 8 and 9 per cent of their annual income tax to the Church. This tax is deducted at source by the state, which passes it on to the Church for a small fee.
After adding other income and subtracting expenses such as salaries the archdiocese was shown to have generated a surplus of €59m (£43m).
The archdiocese's finance director, Hermann J. Schon, described the publication as "a big step towards financial transparency".
The accounts were published in the wake of revelations that the former bishop of Limburg spent €31m (£26m) renovating his episcopal palace, causing thousands of Catholics to officially declare they were leaving the Church.