Other than Cologne, the Frenchified German ones have pretty much all reverted. I still remember reading older historical works or seeing maps that puzzled me with "Treves" or "Spires" or (shudder) "Mayence"; luckily those days seem to be long over...
People forget that French used to be the language of diplomacy so if you wanted to send a letter to the archbishop of Mainz/Trier/Cologne you'd address it to the
prince-électeur de Mayence/Trèves/Cologne. This is one of the reasons the French names really caught on after the Napoleonic wars, because of the increased diplomatic dealings in the Continent. The English names were Mentz/Triers/Cullen - they all survive as surnames.
I for one love traditional exonyms. St. Yves for Setúbal, Coleyn (alternative to Cullen) for Cologne, Osnaburg for Osnabruck, Lunenburg for Lüneburg, Hainault with the old (french) spelling with the L for Hainaut, Dauphiny for Dauphiné, Saragossa, Sleswick/Brunswick, Ottoman Beç for Vienna, Rosetta/Damietta for Rashid/Dumyat, Angora etc. I'd love an option where instead of dynamic names we get traditional exonyms and old-time national spellings eg Graetz, Leipsic, Dantzic - especially uniform Postal Map spelling for all Chinese provinces. It adds a lot to historical immersion!