What is the ruling on praying in a mosque above which flies the flag of the German state?

Muslim minorities in non-Muslim countries must develop their mosques, both physically and spiritually, and adhere to their identity and عقيدة (creed). The placement of flags on mosques should not be a reason to abandon them. Mosques are beacons of light and the محور (pivot) of Islamic identity in those lands. Raising flags is not inherently forbidden; indeed, the Prophet (peace be upon him) used banners. The concern lies in a Muslim raising flags of disbelieving nations as a sign of assimilation and distorted subservience, or prioritizing the bond of the flag over the bond of Islam. There is no contradiction between belonging to Islam and belonging to one's homeland and its symbols; the sphere of belonging to homelands falls under the sphere of Islam. Even if raising flags of disbelieving nations were considered forbidden, this does not necessitate forbidding prayer in a mosque where such flags have been raised. Prayer has its own specific conditions, and no one has ever claimed that raising a flag affects the validity of prayer.