The Turkish-Islamic Union for Religious Affairs (DITIB) is the largest umbrella organization of mosques in Germany. DITIB manages about 900 mosques in the country, including the central mosque in Cologne, and has about 800,000 members throughout Germany.
Its ties to Turkey are very strong. According to the official research service for the German Bundestag, which has created a register of Islamic organizations in Germany, its charter states that DITIB is "linked to the Turkish government's Directorate of Religious Affairs (Diyanet)."
The Diyanet sends Turkish imams to DITIB mosques; the imams' salaries are then paid by the respective Turkish consulate general for the duration of their stay. In other words, the Diyanet determines the theological guidelines behind what is preached in the mosques.