Given the circumstances, I assume that they mean either a date or some kind of blessing or epigram. The latter is particularly probable because the pair of the second and the third symbol is repeated (such as in, e.g., "que sera, sera").
However, I could not identify the symbols. At least the first and second symbol are not part of the German alphabet. In fact, I did not find any alphabet that contains all of these symbols.
Obviously, I don't know the solution to this puzzle yet. However, if you present me a convincing one, I can go to the inhabitant of the house and ask him (but I would prefer not to).