"If this attempt had succeeded, it would have been a disaster for Turkey, Germany and the region," Secretary of State for Foreign Affairs Markus Ederer said after seeing the damage to parliament from bombs dropped by F-16 jets.
He offered Berlin's support in punishing putschists but stressed actions should be "within the rule of law".
"It is essential that these criminal investigations are conducted in accordance with international norms -- European Union, Council of Europe and OSCE standards," Ederer told a press briefing at the parliament building in Ankara.
Relations were already strained over the German parliament's decision in June to brand as genocide the World War I-era Armenian massacre by Ottoman forces.
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During a huge rally yesterday in Istanbul attended by more than a million people, Erdogan again attacked Berlin and warned "terrorists" would hit Germany.
"Germany did not allow the video call, where is the democracy? But they let those in Kandil (do it) via video," he said, referring to a PKK mountain stronghold.
Ankara has come under attack from its western allies who have expressed concern over the post-coup crackdown.
Over 60,000 people from the military, judiciary, civil service and education have been dismissed, detained or put under investigation for suspected links to US-based Islamic preacher Fethullah Gulen. Journalists have also been arrested.
Gulen is accused by Turkey of "ordering" the July 15 putsch. Ankara also describes his movement as a terrorist organisation.
The cleric, in self-imposed exile since 1999, denies all claims and the movement insists it promotes moderate Islam and charity.