I'm pretty sure this is a Monet Goyon fitted with the very rare Villiers 'Pullman' 350cc in line twin.
Monet Goyon is a French make and in the twenties used Villiers engines, first importing them and finally, due to French rules and regulations making them under licence.
When making Villiers engines under licence Monet Goyon tended to change things ever so slightly to suit local requirements so they can be a bit of a puzzle when you see one.
Francis Barnett were the only English manufacturer to try the Pullman twin (In 1928 if I remember rightly) but it was not a success. You can find a picture of one in the photo gallery on the Francis Barnett Owners Club website.
Monet Goyon tried for a bit longer but with little better success.
Cheers, Bob