The Germans did build their own training camp for the World Cup, called Campo Bahia, in Santo André, south of the state of Bahia. The project was a collaboration between German businesses and the German Football Federation (DFB).
The beachside grounds span 15,000 square metres and, within that area, there are 14 two-storey villas comprising 64 residential units. Each villa is housing up to six players of the 23-man squad as well as members of a 39-strong backroom staff. Within Campo Bahia, there is also an outdoor swimming pool, a spa, a lounge and dining area, a fitness centre, communal lounges and an auditorium for team meetings [1]
There was a lot of myths and speculation on what would happen to the hotel. False Facebook threads saying that the hotel would be donated, and even this BBC article that said that "A football youth academy and an orphanage will be built on the site" (I only found this information in non-Brazilian media outlets. I searched for Portuguese references for it. I couldn't find anything that linked a German football team and an orphanage.)
But in the end, the hotel was opened for business as a luxury hotel:
A diária mais "suave" no Campo Bahia custa 600 euros (R$ 1,8 mil), para uma vila com quatro quartos, e a mais cara, 2,5 mil euros (R$ 7,5 mil), para uma vila com seis quartos [3]
(translated) The most affordable daily price in Campo Bahia costs 600 euros (R$ 1800) for a villa with 4 rooms, and the most expensive costs, 2500 euros (R$ 7500) for a villa with 6 rooms