Ankara believes that the six individuals are supporters of Fethullah Gülen, a preacher in exile in the USA whom the Turkish government accuses of instigating the putsch on July 15th, the SZ reports.
Four of the German citizens - a married couple and their two adult children - are from Lower Saxony. While the two children reportedly live in Turkey, the parents were on holiday in the country during the coup attempt, which led to hundreds of deaths.
The entire family was detained in early September before being released again a few days later, according to the SZ.
A 48-year-old woman from Baden-Württemberg and her 25-year-old daughter, a student at a German university, have also been prohibited from leaving the country.
All of the people in question are German citizens who do not have dual Turkish citizenship. They do however all have Turkish heritage.
On a visit to Ankara in August, permanent secretary in the Foreign Ministry Markus Ederer appealed to Turkey for the release of the woman from Baden Württemberg. He also said that Germany expected Turkey to abide by the rule of law while prosecuting coup plotters.
After a rogue military faction tried to oust President Recep Tayyip Erdogan, Ankara launched a massive crackdown, dismissing and detaining tens of thousands within the judiciary, the police and the education system over alleged links to the putschists.