To what extent was there interaction between Europe and Africa beofre the start of the Renaissance? If we looked in a port city in Italy or somewhere else around 1300, would there have been any traders from Africa there?
Well, Spain & Portugal was conquered and run by the Moors for about 800 hundred years between approx 700 and 1500. The Moors, though nominally Arab, where actually mostly Black African and Berber. I suspect that counts as interaction.
Major trading ports such as Venice certainly had a significant black presence. As for Britain, I’ll have to settle for the African drummers employed by the Scottish court of James IV, around 1500: http://www.nationalarchives.gov.uk/pathways/blackhistory/early_times/moors.htm
This site gives much detail about the black population of Britain in historical times :-
http://www.nationalarchives.gov.uk/pathways/blackhistory/intro/intro.htm
You may want to clarify your question, since there were traders from Africa crisscrossing the Mediterranean well over two thousand years ago. Do you mean sub-Saharan Africans? The northern coast of Africa has been economically associated with Europe since at least the Carthaginians.