I don't have a final opinion on this. But I will add that Wikipedia is a weak argument, because just as here, anyone can change the name there. 

From my point of view, the French language is decentralized (just like English) unlike Ukrainian. It is spoken by many people in different countries. These are France, Québec and many other countries in Africa. Therefore, it is necessary to look at the practice of application everywhere and not only in France. I don't know how Kyiv is usually written in France, but in Canadian French-speaking resources the name "Kyïv/Kyiv" is commonly used