This website has scanned copies of civil registers from Köln for births, marriages and deaths.
They seem to range between 1830s and 1870s.
There is no search function but the scans are sorted to make searching them easier.
You are both welcome.
I am actually trying to find a birth record from 1906 and have been getting passed around various government departments for several weeks now :)
I got this link from the archivists but because 1906 is so recent they have suggested i contact the registry instead, so now i am waiting to hear from them.