...to Germany's Commerz Grundbesitz Gruppe for 90 million euros ($124.8 million).
Quinlan said it had bought the downtown Charles Square Center for 56 million euros in 2003.
The centre has 15,000 square metres of office and 5,000 metres of retail space.
The Prague property market has been booming thanks to fast economic growth in the Czech Republic, a European Union member since 2004.
Yields from office space have fallen close to western European levels as real estate prices have soared, outpacing rents.