Pierre Duval was a 19th century sewer worker.
By the time he met Roz Forrester and the Seventh Doctor, he was blind. When Montague discovered Jean Mayeur's body-swapping trick, he killed his other potential hosts. Mayeur was finally forced to transfer into Duval, his last host, where he was incapacitated by Roz Forrester and the Seventh Doctor. (PROSE: The Death of Art)