My question is: the city of Turku has honoured a famous dutchman. Do you know the name of the person? Thanks for the effort. Greetings from Holland.

There is a street called Peter Thorwöste road in Turku. Peter Thorwöste was a dutchman, who lived in Turku in the 17th century, and died here 1659. He was a well-known tradesman and industrialist, he founded for example ironworks in Fiskars. Some further information about Fiskars you can find here:

http://www.fiskars.fi/pdf/Fiskars_history_eng.pdf

Could this Peter Thorwöste be "the famous dutchman" you are looking for? If he is not, could you please give us more information about the man you are trying to identify. When did he live? What did he do for living?