Largest Non-Capital Cities by Continent

We've varied some data in citypopulation.de to give (we think) more sensible answers; that website generally includes vast swathes of countryside plus neighboring cities in their calculations. So,(1) we have separated Johannesburg out from Pretoria, thus qualifying it as an answer; (2) the population of the European side only of Istanbul is given; (3) c.de lists Cologne and Dusseldorf as a combined agglomeration which would have qualified it as an answer, but separated out, as we have done, neither city makes it.