The German website Local reported that the fire department had been called in to put out a fire caused by a suspected arson attack at the Koca Sinan Camii Mosque shortly after 2 am (0100 GMT) on Sunday morning.
The blaze reportedly came under control after an hour.
The incident follows a similar suspected arson attack on a mosque in the administrative region of Stuttgart.
Police have launched an investigation into an arson attack against Muslims at a mosque near the German town Lauffen. Stuttgart prosecutors and local police said on Saturday that they were handling the investigation as a possible racist or anti-Islamic attack.
Five people, who allegedly threw Molotov cocktails into the place of worship, were being prosecuted for attempted murder, according to the German law enforcement agency and judiciary.
The attack on the mosque, which took place on Thursday night, caused material damage but no deaths or injuries.
The congregational prayers leader, known as imam, managed to extinguish the fire at the site.
According to sources in the German Interior Ministry, there were 950 registered attacks on Muslim individuals and properties in 2017 alone. Dozens of people were injured in those attacks.
Meanwhile, Amnesty International has sounded the alarm about right-wing parties in Europe advocating anti-immigration and anti-Islam policies
Germany is home to some three to four million Muslim Turks.
Gokay Sofuoglu, the chairman of the Turkish Community in Germany, which groups 270 member organizations linked to the ethnic group, denounced the attack on Saturday.