In a letter delivered on Sunday to church authorities, the Frankfurt Catholic Association questioned Bishop of Limburg Franz-Peter Tebartz-van Elst and the leadership of the diocese.
The letter said: “The diocese must immediately change tack.” The protesters said that they were “greatly concerned” about the growing crisis of confidence in the diocese, newspaper the Frankfurter Allgemeine reported.
The letter was read out in Frankfurt Cathedral after a service on Sunday and has also been sent to other towns in the diocese.
According to a report on the website of the Frankfurt Catholic Church, 500 people have signed the letter which is seen as a show of support for Frankfurt's deacon, Johannes zu Eltz, who is a critic of the bishop.
The Frankfurter Allgemeine said the deacon had interpreted comments made by the bishop in the past as a call for his resignation, but this was disputed by the diocese. The newspaper said this prompted the letter on Sunday.
Protesters are also calling for a more modest leadership style citing Pope Francis as an example.
The bishop has received criticism in the past. Last year he was criticized for taking a first class flight to India.
The diocese denied that comments made by the bishop were a call for the deacon's resignation.