Yes this is true. He almost married the daughter of "the" Brazilian press tycoon. I read the details in one of his books, probably "Une sacrée guerre!" , "A Damned War!" (very long interview by Daniel Costelle, whom I don't quite take seriously to say the least, but PC is all right). By the way, PC was a very young, professional journalist long before he went to war. A most talented man! Brazil considers him a Brazilian citizen for he was borne there. There is a street named "Coronel Clostermann" in his birth city I think - Curitiba - and possibly in some others. Let us remember that Brazil declared war on Germany and was one of the Allied countries.
More details some other time (1.24 hrs now here - I was fighting with some PC software...). Wyatt Earp just won against the bad guys on TV, which is a big relief.