It is the capital of Canton of NeuchÃ cents tel . . After the fall of Napoleon , Frederick William III of Prussia reasserted his rights by proposing that NeuchÃ cents tel be linked with the other Swiss cantons ( the better to exert influence over the lot of them ) . On September 12 , 1814 , NeuchÃ cents tel became the 21st canton , but also remained a Prussian principality .