a house in cologne ehrenfeld. unfortunately i haven’t found any information on the artist. so if you can help out please do it in the comment section below :)
UPDATE: the mystery is solved! a big thank you to sheffield and the fantastic Mr C – the mural was done by british artist Lucy McLauchlan in 2011.
.documenting.the.obvious 
My first thought when I saw this was that it was a piece by UK artist Lucy McLauchlan http://lucy.beat13.co.uk/ It appears to have signature elements of her work. She has a website and blog at the link above. Best wishes, Mr C :-)
Bingo! Thanks a lot, Nigel. Much appreciated!