Closuit have been citizens of Martigny-Ville since before 1800 - the only place of citizenship for this name. As the person you are looking for will likely have left Switzerland after 1875, he and his parents should be registered at the Etat Civil Martigny
: contact them and ask
- if Paul Closuit can be identified on their register, if yes
- what you are expected to do (and pay) to get his parents' "family sheet".