Berlin is one of the great European cities, and I cannot consider accommodation in anything which doesn't adequately represent the culture and learning of a city. In Berlin this can be experienced in one of the grand hotels, whose budget alas is way beyond reach, or in a city pension, but one that is family-run and comfortable.
Bregenzer Strasse is in the city area of Charlottenburg-Wilmersdorf, The 'dorf' part of Wilmersdorf became history when it was connected by tram to the old centre of Berlin (a few kilometres eastward) around 1870, but this area was settled in the 12th century. The 'burg' part of Charlottenburg on the other hand is very much extant and well worth a visit.
The pension has if I recall rightly 15 rooms and those looking into the 'hinterhof' (the inner courtyard of an urban residential structure) may be marginally quieter than the others. The couple running this charming and excellently maintained example of old Berlin hospitality are attentive, understanding of the needs of guests and look after the details with care.
A pension is not a hotel, and a hotel can never be a pension. A room at a pension may cost a little more or less than the typical city hotel, but has atmosphere and a connection with gracious living that the modern hotel cannot duplicate. The old-fashioned and perfectly functional period lift (elevator) was delightful, as were the generous breakfasts.