The report says the demand for serviced apartments was "constantly increasing as the working environment changes and the number of permanent commuters spending the work-week away from home grows".

The pipeline for 2017 to 2019 is dominated by Munich (with 2,313 units), followed by Berlin (1,750). By 2019, 7,516 units are planned for the top seven German cities.

"The growing interest in serviced apartments is happening mainly from the consumer side," said Christian Ott-Sessay, managing director, Horwath HTL Germany. "In this case, consumers are business guests, students or tourists. The reasons vary from changes in the job market, limited living space for students in  popular university cities to a general growth in touristic demand in Germany."

He added that a key factor was the "economical advantage of serviced apartments - saving up to 50 per cent compared to hotel costs-and the cost consciousness of international business demand".

Svenja Brau, consultant at Horwath HTL Germany, said: "The serviced apartment concept regarding residential concepts is attractive for investors as the model delivers higher returns than, for example, rental revenues. The investors being interested in entering the serviced apartment market vary from institutional investors to family-businesses. But still, the market is fairly new and the coming years will show clearer tendencies."

According to the Horwath HTL study, domestic operators such as Derag Livinghotels and Adina Apartment Hotels dominated the German market, but the international chains have an increasing market share, currently at around 11 per cent.

Ott-Sessay said: "The brand is of great importance, which can also be seen in the products that have recently entered the market. Renowned brands as Hyatt and Accor's Adagio have recently entered or even enlarged their activities in the German serviced apartment market with their brands Hyatt House and Adagio Access. Vienna House also launched their new long-stay concept Vienna House Basecamp."