It is another much obscure say, 'project' of microcar...
In fact, I've discovered its existence on a very famous auction website. I guess it is the same for you, Wendax !
It is the Monocab, built by les Etablissements Fouga & Cie, aka Les Ateliers d'Aviation d'Aire-sur-Adour. The advertisement I've seen is saying it is built under "Armand Citroën licence".
This is quite weird, because I've read some tiny bits here and there about the Joseph Citroën Monocab. Joseph Citroën was a cousin of André Citroën. The Joseph Citroën looked quite like the "Fouga/Armand Citroën".
So, was it his brother ? Were they worked together on the same car ?
Strangely, the name "Fouga" is quite well know too, but in the airplane industry : they made the "Magister", the very first training jet-plane, built for the apprenticeship of pilots.
The document printed for the Monocab says it used a 2-stroke, 1-cylinder engine, a patented suspension and is able to get to 40 km/h...
I don't know when this small brochure was made, but Joseph Citroën made some advertisements for the Monocab in 1954...
If anybody knows anything more, or have some pictures of the Joseph/Armand Citroën, I'd love to see and read it !