Ok, this is how it works in France
Ordinary Aircraft get F-GEKO or whatever. That's a real one, you can look it up. Or F-Hxxx now that they have run out of F-Gxxx
Homebuilt get F-Wxxx until the test program is complete. Then it's F-Pxxx
Gliders get F-Cxxx
Gendarmes and customs get F-ZBxx or F-MJxx (might be the other way round, but you get the picture.)
Historic or collection you get F-AZxx even if it's a glider.
There are others.
Microlights are completely different. They get the department number plus letters (two or three) For example 22IS. Under the wing and on the fuselage. Unless there isn't a wing, (autogyro or helicopter) or indeed a fuselage as such (powered parachute, weightshift) They keep this number even if they move house, on sale or the owner changing department.
Now this is where it gets silly. If you want a radio in your microlights you can put one in, but it is identified to YOU not the machine. That would be F-Jxxx. One radio can be used in more than one machine, and each machine can have more than one radio...You need to declare all this, showing how the installation is done. This is the callsign you use, not the 22IS or whatever. You aren't allowed to put the radio id on the outside. But people do.
Confused? Never mind. Thats just the way it is.