This 2-wheeler was made in France from 1925 to 1928, under licence from Mauser of Germany. (Yes, that Mauser) It had two retractable stabiliser wheels. The passenger sat behind the driver (unlike the remarkable Sabella tandem car of 1913, where the driver sat behind the passenger)
It was powered by a 510cc single. Very few were made and even fewer survive today.
La Monotrace was made in St. Etienne, France.
The remarkable Monotrace has its own page: see link above or click on picture.
Picture by kind permission of the restorers: KOHLER AG,
Riedtwil