Hi "guest" ! I was born and still live in Geneva for 62 years ! "Jean Calvin" IS (was) his real name, as he was a "Genevian" too !
Calling him "John Calvin" is totally wrong and even translate his name in latin -Ioannes Calvinus- is wrong, as people was speaking -and still speak- FRENCH in Geneva (church people were speaking latin for some matters at school, and during the masses, only !).